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Talk:Voronoi diagram

Dual to Delaunay triangulation?
This is the dual to delaunay triangulation, isn't it? Chas zzz brown 10:37 Feb 2, 2003 (UTC)

 * Correct --- and that article is even stubbier than this one. Maybe I'll work on both of them further at some point.  Michael Hardy 22:28 Feb 5, 2003 (UTC)

Wigner-Seitz cell
Another Example is the Wigner-Seitz cell in materials science.--149.220.16.110 15:30, 15 September 2006 (UTC)

John Snow's cholera map
Is it true that John Snow used a Voronoi diagram to illustrate his investigation of the cholera epidemic? I've seen some of his maps, and don't recall seeing a Voronoi diagram (or even an approximation to one) on any of them. Gareth McCaughan 00:24, 2005 Apr 10 (UTC)

 * See Figure 12.6 at . The text explains that Snow plotted a line that was equidistant between the Broad Street pump and alternative pumps, so I think it qualifies as a simple Voronoi diagram. Gandalf61 07:48, Apr 11, 2005 (UTC)

 * Aha. The Voronoi line wasn't present in Snow's map in On the mode of communication of cholera (1854), which is the famous one reproduced in a million different places. It's there in his report to the Cholera Inquiry Committee in 1855. I agree that it qualifies as a simple Voronoi diagram. Perhaps a link to http://www.epi.msu.edu/johnsnow/Snow%20pub%20doc/CIC-JSRpt_SF12.htm (his CIC report), or to the page you mentioned above, should go in the References? Gareth McCaughan 09:12, 2005 Apr 11 (UTC)

Artwork; unusual statements
This article already has some nice graphics; are we sure its a good idea to also add ascii art to this? I don't think so ...

Also: there's talk about a rectangular tesllation with points "not at the center" ... how can that be? its a metric polygon; is this a subtle statement that the center of mass doesn't align with the metric center? Besides the "center of mass", there are other types of "centers" e.g. center for diffusion processes, etc. How about other definitions of "center"?

Also, for a rectangular array, the voronoi cell is not a rectangle any more ... so the "examples" section has several confusions in it ... ditto for the remarks about isocleles trinagles ... linas 20:28, 26 July 2005 (UTC)

Algorithms?
How about adding some mention of the algorithms used to calculate a voronoi diagram? IIRC, there is one that works in O(n*log(n))?

 * If you can describe such algoritms accurately, then please add them. linas 16:07, 23 November 2005 (UTC)

pronunciation?
Voronoi appears to be of Ukranian descent.--MinorEdits 08:45, 1 June 2006 (UTC)

Additional Material to Consider for Uses and Application
"Spatial Query Processing Utilizing Voronoi Diagrams" from the Google TechTalks series: http://video.google.com/videoplay?docid=-2755539754474649930

Order of a Voronoi diagram
It might be helpful to talk about the order of a voronoi diagram. E.g. something along the lines of, "a Voronoi cell can be generated from a set of points from S. The cardinality of this set is referred as as the order of the Voronoi diagram". It might also help to give algorithms for constructing order-k diagrams and the complexity of generating an order-k diagram. —Preceding unsigned comment added by Sunupsundown (talk • contribs) 19:45, 1 October 2008 (UTC)

Non mathy?
The concept behind Voronoi Diagrams can be explained in non mathematical terms/notation (ok, you need points, lines and distance, but not much more then that). With the help of a picture, shouldn't that sort of explanation be in the introductory blurb?

Also, it would be interesting to know what "human algorithms" were used to draw 2D voronoi diagrams back before computers.

A non-mathy observation: doesn't the Voronoi iteration explain the approximate cultural and sometimes political boundaries for countries with land borders adjacent to others? That is, the farther from the capital, the weaker the influence. A real world example like this would be useful. —Preceding unsigned comment added by Bobbyleeds (talk • contribs) 15:45, 13 August 2010 (UTC)

 * I did a quick Google search for this. I couldn't find a national-level example, but I did find an example for the states of the USA. Not sure how (or whether) to include it in the page though. The applications is already a bit messy... Warrickball (talk) 10:23, 22 August 2011 (UTC)

This article assumes one is familiar with terminology and even goes to obnoxious lengths to introduce it when it's not necessary. In other words: this article has been written by a group of insufferable twits. Speedy deletion. — Preceding unsigned comment added by 82.249.88.27 (talk • contribs) 29 October 2012

 * I've removed the incomplete WP:AFD nomination of the article. From the above comment its clear you ment the nom more as a protest rather than an actual case for deletion.--Salix (talk): 09:28, 29 October 2012 (UTC)

 * I've simplified the lead section which should make it a little simpler.--Salix (talk): 09:45, 29 October 2012 (UTC)

Fermat point
If you have just three points do you get the Fermat point? --Salix alba (talk) 22:22, 24 September 2007 (UTC)
 * Nope. The Voronoi point is the intersection of orthogonal bisectors, i.e., of lines perpendicular to the sides of the triangle pasing through their middles. So you may easily prove that it will be the Fermat point only for an equilateral triangle.`'Míkka 06:24, 25 September 2007 (UTC)
 * It is the circumcenter, though. We could say, in the properties section, that the mutual boundary point shared by any three adjacent points is their circumcenter. PhiloMath (talk) 16:39, 10 December 2007 (UTC)

Software
I deleted the software section, since there is really a lot of software that can do it and I don't think we should be in the business of plugging a particular package. If you do add it back, I would like to see, eg, qhull mentioned. --Dylan Thurston 17:43, 1 October 2007 (UTC)

Algorithm?
An easy algorithm for creating a Voronoi diagram would seem to be, for each pair of points, to draw a line between them, and then to draw a boundary perpendicular to that line, crossing it at its exact centre. The segments created by these boundaries then make up the cells in the Voronoi diagram. But what happens if this algorithm creates segments without a point inside them? J I P | Talk 13:47, 8 October 2007 (UTC)
 * You could take the set of perpendicular bisectors, which will form a super set of the Voronoi diagram, And then search for those segments which form a polygon around each vertex. Whether this will be efficient is a good question and there has been a lot of work on efficient algorithms. In practice I'd recommend the Qhull program (see links) which works by computing a convex hull in n-dimensions. --Salix alba (talk) 15:40, 8 October 2007 (UTC)
 * Delaunay triangulation (the dual problem) has some more details of algorithms. --Salix alba (talk) 16:11, 8 October 2007 (UTC)

Space complexity mentioned in the Generalizations section
It's mentioned in the generalizations section that it requires at least O(n^floor(d/2)) space for a Voronoi diagram in d dimensions. This doesn't really make sense, though, just because you don't want to use big-Oh here, but rather omega, I think. If you use big-oh, you're saying "it takes less than X space, which is too much!" since big-oh is basically a <= or < type inequality, depending on case, whereas omega is > or >=.

 * They may not have lower bounds on the running time for all higher dimensions, but believe that the bounds are tight. In 3D, however, the worst-case bounds are known to be both O(n^2) and Omega(n^2) (i.e. Theta(n^2)), see http://www.math.tau.ac.il/~michas/wads95.pdf. If they only give big-Oh, that usually means that its the best worst case upper bound known, and may be achievable by some inputs. So O(n^2) is also O(n^3), but if you knew an algorithm was O(n^2), you would say that and not O(n^3) so that it is known that as far as we know it could take up to quadratic space but never requires cubic-space. --128.119.40.196 (talk) 16:05, 9 July 2013 (UTC)

Also, it doesn't really make sense to say any dimension above 2 is out of the question. You could probably say instead that it doesn't make sense for $$d>>2$$, or for "large d" (for d=3 it is not so bad, for non-gigantic point sets). PhiloMath (talk) 16:45, 10 December 2007 (UTC)

I am actually not convinced with the expression itself. With the given formula, it is O(n^2) for d=3. This means that if I have 1000000 points and I add one more, the increase in the required space will be proportional to 1000000. On the other hand the graph will be effected only locally, so why would I need ~1000000 extra bytes to represent that. It is actually further in question since a set of points define a unique vronoi diagram, just storing those points in itself is a way of storage and this has O(n) complexity. Therefore the storage implementation is also a factor and it should be stated. I'm not an expert on the area, so what I say might be complete nonsense, but I still think that part begs a citation. I've checked the reference about space efficient representation, and it doesn't say much about the expression in question. Enisbayramoglu (talk) 12:45, 16 March 2009 (UTC)

 * I haven't looked into this, but it may just be the best upper bound we can prove. Clearly adding a single point can effect all the other voronoi cells. A pathalogical example, place all of your 1,000,000 points along the x-axis at the integers 1, ..., 1,000,000. Then your VD is made up of exactly 1,000,000 planes, each orthogonal to the x-axis at positions 0.5, 1.5, 2.5, ... Now add a single point somewhere like (500,000, 500,000, 500,000). I believe this will require each of the original 1,000,000 Voronoi cells to have a new facet added (and thus add 1,000,000 facets to the VD). Tight bounds are proven here: http://www.pi6.fernuni-hagen.de/publ/tr277.pdf--128.119.40.196 (talk) 15:50, 9 July 2013 (UTC)

 * Here: http://cstheory.stackexchange.com/questions/17331/outer-part-of-voronoi-diagram-in-3d in the solutions two point sets are described which require Omega(n^2) in 3D.

Discrete set of points?
In the Definition section of the other article it claims that "For any (topologically) discrete set S of points in Euclidean space and for almost any point x, there is one point of S closest to x". This is untrue as shown by the example in the Discrete space page {1, 1/2, 1/4, ...} using the usual euclidean metric: Any negative number has no closest point in the set. It seems to me that some additional restriction like "no accumulation points" is required. TomC phys (talk) 02:28, 12 February 2009 (UTC)

 * Actually, S just needs to include all it's limit points. Including 0 in your example fixes it with no problems. Nekura (talk) 03:03, 25 June 2009 (UTC)

 * Thinking more about it, is it really a requirement, or does it just make the diagram look nicer? The original definition starts with finite sets, so "closest point" could be defined for every point c in the space. But is it "required" that every point c have a closest point, or is it just a relic from the finite case? Is it the set of points in the space, or the set of cells associated with each point in S? Nekura (talk) 03:54, 25 June 2009 (UTC)

Question about existence
If I have a general graph consisting in a set of points and links among them, can I associate to it a "triangulation" in some sense? I mean, regarding the graph as a Voronoi dual to the former triangulation. If yes, can I do it for any d-dimensional generalization of triangle cells or are there requirements to fulfill? I'd like if someone is able to point me out an answer and eventually a reference. I'm posting this question also in Delaunay's triangulation page. Omar.zanusso (talk) 10:33, 5 March 2009 (UTC)

Conflict between Introduction and Definition
In the introduction, a Voronoi diagram is defined as a decomposition of a metric space (any), but in the "Definition" section, it is spoken only of Voronoi diagrams in Euclidean spaces. 00:29, 19 June 2009 (UTC)

Also it should be a clarification between the general definition of Voronoi diagrams (i.e., of any order and within any metric) and the usually known as "Voronoi diagram" that refers to a first-order Voronoi diagram in euclidean space. --RedBlackTreeNode (talk) 07:20, 30 September 2011 (UTC)

Weighted Voronoi Diagrams
I'm looking for information on weighted Voronoi diagram. Google only gave me references to programs that do it. There should be a section on it, including the difference between Multiplicative and Additive. Nekura (talk) 00:41, 25 June 2009 (UTC)
 * Here you are. - Altenmann >t 18:59, 26 June 2009 (UTC)

Higher-order Voronoi diagrams
This article says:
 * Although normal Voronoi cells are defined as the set of points closest to a single point in S, Nth-order Voronoi cells are defined as the set of points closest to n points in S. Higher-order Voronoi diagrams also subdivide space.
 * Higher-order Voronoi diagrams can be generated recursively. To generate the nth-order Voronoi diagram from set S, start with the (n − 1)th-order diagram and replace each cell generated by X = {x1, x2, ..., xn−1} with a Voronoi diagram generated on the set S − X.
 * Higher-order Voronoi diagrams can be generated recursively. To generate the nth-order Voronoi diagram from set S, start with the (n − 1)th-order diagram and replace each cell generated by X = {x1, x2, ..., xn−1} with a Voronoi diagram generated on the set S − X.
 * Higher-order Voronoi diagrams can be generated recursively. To generate the nth-order Voronoi diagram from set S, start with the (n − 1)th-order diagram and replace each cell generated by X = {x1, x2, ..., xn−1} with a Voronoi diagram generated on the set S − X.

I find this quite unclear. How do you measure distance to a finite set of points? Is it the sum of the separate distances? If so, it should say so, and if not, it should say what it is.

Next, suppose I want to generate the 2nd-order Voronoi diagram. I have a set S of points and I draw their Voronoi diagram. I presume that's the "1st-order" Voronoi diagram. We have n = 2. So I am told to "start with the 1st-order Voronoi diagram and replace each cell generated by X = {x1} with a Voronoi diagram generated on the set S − X." Delete points one-at-a-time and draw separate Voronoi diagrams? And this tesselates space? This doesn't make sense. Michael Hardy (talk) 11:45, 11 August 2009 (UTC)

OK, I found this web page. It says two points are in the same nth-order Voronoi cell if they both have the same set of n nearest neighbors in S. That is clear. The text above says "closest to n points in S". That is utterly unclear: it requires us to measure the distance from a point to a set of n points in S, without saying whether that means a sum of separate distances or what. I don't understand why people write like that; it's just abusive to the reader. (Maybe changing capital N to lower-case n in mid-sentence should warn us that whoever typed this wasn't paying attention.) Michael Hardy (talk) 11:58, 11 August 2009 (UTC)

...the second paragraph is still unclear at best. Michael Hardy (talk) 11:59, 11 August 2009 (UTC)

Recently Added Link
The link which was recently added "V*-Diagram: A Highly efficient technique for processing moving nearest neighbor queries" seems to be an author referencing their person research which is related to Voronoi articles but clearly outside the scope of a general article on the subject. I will remove this link soon unless someone objects. RuppertsAlgorithm (talk) 01:23, 11 September 2010 (UTC)

WorldMap.pdf
New external link:

 * A Voronoi diagram on a sphere

I downloaded this but see no content other than a caption. How about you? —Tamfang (talk) 01:47, 12 July 2012 (UTC)

Blank for me too. // NomadicVoxel (talk) 01:53, 4 July 2021 (UTC)

real life voronoi
Interesting maps appeared on Reddits /r/mapporn including two real life maps of the US and world as a Voronoi diagram. They here and here. They should be added ASAP in my opinion rather than duplicating the one you have now. I hope it is changed but I do not know how to do so. 92.23.66.70 (talk) 15:37, 3 July 2013 (UTC)

Dead link to Melbourne school zones
The site melbourneschoolzones.com has apparently shut down due to a price increase on the Google Maps API, and the version on archive.org doesn't really work without JS, suggest the link is removed, maybe along with the entire section as it's not very useful without the map. — Preceding unsigned comment added by 129.194.48.105 (talk) 10:45, 27 January 2020 (UTC)

Suggestion to simplify the first paragraph
The first paragraph feels kind of dense to me and I was about to edit it, but being new to the editor side of Wikipedia, I was unsure if I should actually submit it. Thoughts? "...or in other words, a Voronoi diagram is map shaded to indicate where the nearest significant point is from any location." — Preceding unsigned comment added by NomadicVoxel (talk • contribs) 07:07, 5 May 2020 (UTC)

What are "adjacent" points on a convex hull? Clarification is needed
The section Properties contains this passage:

"Assume the setting is the Euclidean plane and a discrete set of points is given. Then two points of the set are adjacent on the convex hull if and only if their Voronoi cells share an infinitely long side."

But what does it mean for two points of the set to be "adjacent on the convex hull" ???

I hope someone knowledgeable about this subject can clarify this for readers. 2601:200:C000:1A0:F447:6226:63A4:B204 (talk) 19:16, 11 May 2022 (UTC)
 * What do you think it means for two vertices of a polygon to be adjacent? —David Eppstein (talk) 19:31, 11 May 2022 (UTC)

Information about the surface area of cells relevant?
Today, I made an addition to the page that was removed because it cites my article. I believe the suggested modification is interesting and pertinent enough to be included, but I acknowledge my strong bias and so I leave this issue to be resolved by the community. Thanks, Ryan. Ryancots (talk) 15:41, 28 December 2022 (UTC)

 * I have a few concerns besides COI about your proposed edit. WP:PREPRINT for one. Also, this property sounds like it might be a property of any partition into convex sets with marked points, and not a special property of Voronoi partitions. I would also want the property to be described in a style similar to the other properties, and not in the style of a math paper. Eigenbra (talk) 17:45, 28 December 2022 (UTC)
 * Great, thanks for checking out the edit, and thanks for your feedback. Ryancots (talk) 10:29, 29 December 2022 (UTC)

section

 * In general, a cross section of a 3D Voronoi tessellation is not a 2D Voronoi tessellation itself, since the cells are all convex polyhedra.

Both parts of this statement are clearly true, but the applicability of "since" is not obvious to me. —Tamfang (talk) 03:07, 25 August 2023 (UTC)

 * I agree. Edited to remove that clause entirely. Eigenbra (talk) 13:34, 25 August 2023 (UTC)

fundamental definition should be points in the Euclidean plane, not arbitrary metric spaces
This article uses an overly abstract definition that is rare in practice (by at least an order of magnitude I would guess) and overly technical for much of the intended audience. I think it should be refocused on the Euclidean plane case, with a more abstract / general definition deferred to a section about generalizations. Let me recommend a first paragraph along the lines of:

 * In mathematics, a Voronoi diagram is a partition of the Euclidean plane into regions close to each of a given finite set of points (called seeds, sites, or generators). For each seed there is a corresponding region, called a Voronoi cell, consisting of all points of the plane closer (at smaller distance) to that seed than to any other. The Voronoi diagram of a set of points is dual to that set's Delaunay triangulation. The concept of a Voronoi diagram has been generalized to use objects other than points as the seeds and to settings of higher dimension or more generally to arbitrary metric spaces with an alternative notion of distance.

This would then simplify much of the later presentation which repeatedly adds "in the Euclidean plane" or the like as a qualifier. –jacobolus (t) 20:10, 3 September 2023 (UTC)

I made a O(n) voronoi algorithm
One really simple O(n2) algorithm isn't described in this article. Here's the pseudocode: Given n seeds in a plane: For each seed S(i) where i=0 to n-1 For each seed S(j) for j != i         Generate an "infinite" half-plane with its boundary bisecting the line connecting S(i) and S(j), with the half-plane containing S(i). The "infinite" extent need be no bigger than the span of seeds. Perform a constructive solid geometry intersection operation with this half-plane and all previous half-planes generated in this loop end inner loop end outer loop

Does anyone know if this algorithm has a name that can be mentioned in the article?

This algorithm results in voronoi polygons around each seed. It's an O(n2) algorithm and I'm surprised it isn't mentioned here due to its simplicity and ease of understanding. The intersection of multiple half-planes at different orientations always results in a convex polygons around a seed that corresponds to a voronoi polygon.

I took this and made it O(n) as follows:

By subdividing the planar region into grid cells and imposing the restriction that each grid cell contains exactly one seed anywhere inside it, each seed is guaranteed to be no further apart than 2 grid cells diagonally. Therefore the inner loop above can be skipped for any seed more than this distance away from the seed S(i), resulting in about 8 intersection operations per seed. This is an O(n) algorithm, actually more like O(8n), and the execution time increases linearly as n increases, rather than exponentially.

I provided a demonstration, documentation, and code here: https://www.printables.com/model/831732 ~Anachronist (talk) 05:17, 19 April 2024 (UTC)

 * See WP:NOR. We cannot include material here unless it has already been reliably published, and this talk page is only for discussions of article improvements, which for new material can only be based on published sources. But also, what do you do when the input sites are not evenly spaced and have no grid with exactly one point inside each grid cell? —David Eppstein (talk) 06:24, 19 April 2024 (UTC)
 * I'm well aware of WP:NOR, you and I have been editing Wikipedia for about the same length of time, and my comment above does contain a suggestion for improving an article, if a name for the O(n2) algorithm can be found. The algorithm is so simple I would be surprised if no one has published it. I've done some cursory searching but haven't found it yet. I didn't create that O(n2) algorithm. I found it originally in a github project. All I did was impose a requirement on the input to cause the algorithm to be O(n), and I know that cannot be included here because as far as I know, that is my own original research. However, at my age, I've grown accustomed to learning that new ideas I get have already been thought of by someone else, so you never know.
 * Your final question makes no sense. If you look at what I linked, you'll see the input sites (I assume you mean seeds) are never evenly spaced. What makes it O(n) is the requirement that each grid cell contains exactly one seed at any random position inside the cell. This still gives you a random distribution of seeds, but eliminates the need to test seeds farther than $$2\sqrt{2}\times\text{gridsize}$$ away from the seed for which a voronoi cell is being generated. If you don't put a seed in each cell, all bets are off; you get a pattern that may have errors because there may have been a seed farther away that needed testing. ~Anachronist (talk) 06:39, 19 April 2024 (UTC)
 * What makes it O(n) is the requirement that each grid cell contains exactly one seed at any random position inside the cell.
 * An algorithm for constructing the Voronoi diagram needs to work with any arbitrary placement of the generating points, not just ones which round to a square grid. –jacobolus (t) 16:07, 19 April 2024 (UTC)
 * That is absolutely false. An algorithm can certainly specify input conditions for it to work. Examples in mathematics abound.
 * For example, the most basic fast fourier transform mandates that the input quantity be a power of two. A sine transform requires the bounds to be zero, a cosine transform requires the derivative at the bounds to be zero. Newton's method requires the starting point to not be near a local minimum in the function, and other requirements to prevent the solution from endlessly oscillating. An algorithm for solving sparse linear systems may require the input matrix to be tridiagonal, block diagonal, banded, or whatever. I could go on. The point is that many algorithms prohibit "arbitrary" inputs.
 * In this case, an algorithm for generating an O(n) voronoi pattern requires an arrangement of seeds with one seed per grid cell, with each seed placed at an arbitrary random location in each cell.
 * But that's all irrelevant. There's no way my idea for an O(n) algorithm is going to get into this article; I knew that already. I am instead asking the community if anyone is familiar with the O(n2) algorithm I described, which I initially found on GitHub, and whether anything like it has ever been published. ~Anachronist (talk) 00:12, 20 April 2024 (UTC)
 * The idea of using a grid, and hoping that most grid cells have few points and few neighbors, is definitely not new. See:
 * A. Maus. Delaunay triangulation and the convex hull of $$n$$ points in expected linear time. BIT 24:151-163, 1984. . (It's Delaunay rather than Voronoi but they're the same thing.)
 * Rex A. Dwyer. Higher-Dimensional Voronoi Diagrams in Linear Expected Time. Discret. Comput. Geom. 6: 343-367, 1991.
 * The difference is that the algorithms from these publications take arbitrary point sets as input, as a Voronoi diagram does, and then analyze their running time as linear for average-case inputs. They do not take the parameters of a grid as input, generate an input from that grid, and only work for inputs that are generated in this way, as yours appears to do.
 * As for the idea that each Voronoi cell can be generated by intersecting $$n$$ halfspaces, one for each other site: this is also standard, and presented in many sources as a description of the Voronoi cells. It is not commonly presented as an algorithm for constructing the whole diagram because it is not very efficient and what's the point of presenting slow algorithms instead of fast ones? And unless you are doing something complicated, your time analysis is incorrect: in 2d and 3d it takes $$O(n\log n)$$ time to construct the intersection of halfspaces and therefore the overall algorithm takes time $$O(n^2\log n)$$.
 * —David Eppstein (talk) 01:34, 20 April 2024 (UTC)
 * Thank you. That first source got the idea: "The expected execution time is achieved when the data are (not too far from) uniformly distributed" — which is the case I proposed, the difference being that there is guaranteed to be one seed in every grid cell, and even though the seeds can be very close together, they can be no farther apart than the farthest corners of two adjacent diagonal cells.
 * As far as I've been able to determine by measuring execution times of my algorithm, it's linear. Each seed requires an intersection of 8 half planes, less at the edges of the data set. The execution time of an intersection between two things (a half plane and the result of the previous intersections) is fairly constant. The algorithm doesn't perform an intersection of all 8 half planes at once, but even if it did, the execution time scales linearly with the number of seeds.
 * You ask, "what's the point of presenting slow algorithms instead of fast ones?" My answer: (a) the article already names the Bowyer–Watson algorithm, which can be O(n2), and (b) the one I describe above is simple for a layperson to understand. Wikipedia article should be accessible by a broad audience. ~Anachronist (talk) 02:02, 20 April 2024 (UTC)
 * Wikipedia articles should reflect published material found in reliable sources, not the partial results of tentative experiments performed by Wikipedians. –jacobolus (t) 08:17, 20 April 2024 (UTC)
 * I agree with that first part of that statement, but you are quite wrong on the second part: my results are not partial and my experiements were not tentative. ~Anachronist (talk) 00:25, 22 April 2024 (UTC)
 * Sorry, that was unnecessary on my part. I don't know the details of what experiments you did, nor was it really relevant to my point. –jacobolus (t) 06:32, 22 April 2024 (UTC)
 * That is absolutely false. An algorithm can certainly specify input conditions – It's not "absolutely false"; I just didn't express my point clearly enough so it didn't get through. For the context of Wikipedia, those input conditions should be broadly relevant to the subject as it appears in reliable sources. If there's a set of non-arbitrary inputs used broadly in the research literature, it's fine enough to mention it in a new section (whose title could be "Faster algorithms for special cases" or the like). Making up new restrictive cases with no previously applied theoretical or practical uses is fine for a new blog post (or research paper), but is entirely inappropriate for a Wikipedia article. –jacobolus (t) 08:25, 20 April 2024 (UTC)
 * Good idea. I hadn't considered writing about this in a blog post, but maybe I should. I haven't contributed to my blog in quite a while. ~Anachronist (talk) 00:25, 22 April 2024 (UTC)

title: Talk:Voronoi diagram


text:
Talk:Nelson, New Zealand

Super beaches and NPOV
IP addresses keep adding the word "super" to describe the beaches. While agreeable, this statement violates the NPOV. I can't fix it anymore today, as that would violate the 3RR. Someone, please help keep this article neutral! --Gray Porpoise 01:18, 21 August 2006 (UTC)
 * If there are sources that describe Nelson's beaches as "Super" and no sources that state they are not "super" then a NPOV mandates that we say Nelson's beaches are "super" too in the article. WP is not concerned with arbitrating truth or opinions - merely summarising in a balanced way all referenced points of view. W. Frank ✉ 22:45, 21 May 2007 (UTC)

Nelson's Māori name, Whakatū
I've reverted the non-consensual excision of Nelson's Māori name, Whakatū, from the lede. Maori is one of NZ's 3 official languages and, if I live long enough, I will propose to one of my children that they propose a special resolution of the City Council to ratify this name on 5 June 2007 - although what Nelson's bypass was named may give you a clue as to whether this name is "official" or not: Whakatu Drive. And yes, I am biased considering that my children are at least genetically 41% Maori ... Gaimhreadhan (kiwiexile at DMOZ)  • 15:17, 19 May 2007 (UTC)
 * PS: Is your friend ever going to collect his dog kennel, Hayden?
 * I've changed the Infobox following (preliminary?) discussion at New_Zealand_Wikipedians%27_notice_board I hope you're feeling a bit better now, G. W. Frank ✉ 21:46, 22 May 2007 (UTC)
 * I'm very much looking forward to seeing my family and Gadfium; I've left the keys to the Transit on your mantelpiece. Thanks for steering the Maori naming discussion in a more temperate way than I probably could have managed... Gaimhreadhan [[Image:Map of Ireland's capitals.png|15px]](kiwiexile at DMOZ) • 12:10, 31 May 2007 (UTC)

Population Growth
I have removed the unreferenced statement about the Nelson urban area having the largest population growth in the country. According to Statistics New Zealand, Nelson experienced 4.2% growth between 2001 and 2006. The national average was 8.4%. dramatic 08:28, 22 May 2007 (UTC)
 * There is a distinction between the statistics for the City of Nelson unitary authority area and "The Nelson urban agglomeration (including the fast-growing adjacent town of Richmond)". I will try and find a reputable source for the text you excised that it: "has a population of approximately 60,000 - and has recently had a population growth rate exceeding any other population centre in New Zealand."W. Frank ✉ 10:29, 22 May 2007 (UTC)

Weather averages for Nelson, New Zealand inaccurate
Quite a few of the temperatures in the table are inaccurate, for example the yearly average minimum of 47 in Fahrenheit and 7 in Celsius. 47 Fahrenheit is 8.33 Celsius.

The biggest error is for September, in Fahrenheit, the average minimum is given as a rather cold 32 Fahrenheit but in Celsius, it is given as a much milder 5 degrees. —The preceding unsigned comment was added by Special:Contributions/ (talk)

 * I suppose that comes from using an American source. I'll go and check the source again W. Frank talk ✉ 22:37, 22 August 2007 (UTC)

 * I've double checked and you're correct. Sorry I made the error when I was transposing them. I've added a Notes section now so you can double check the source I used if you would be so kind? W. Frank talk ✉ 22:52, 22 August 2007 (UTC)

Table of Contents (TOC) position
People access WP using a variety of screen resolutions and operating systems. I believe that all NZ geographic articles now have the Infobox.

The lede paragraphs are always intended to be just a short introduction to (and encapsulation of) the rest of our article.

For the mast majority of readers, it will be a better use of their screen space to have the lede in a "newspaper column" with the TOC to the left and the infobox to the right. This format achieves the minimum "white space" and waste of screen resources and leads to the minimum amount of scrolling needed to read to the end of the article. It is also aesthetically more pleasing.

Those few users that dislike this format can always "toggle off" the TOC display.

Does anyone disagree and, if so, why please? W. Frank talk ✉ 13:20, 4 September 2007 (UTC)

Proposed merge with Flag of the City of Nelson (failed)
I oppose such a merge. The flag is a specialised topic which is probably not of interest to most people looking at the article on the city, but as one of the few city councils to adopt its own flag, it has an inherent notability. A separate article seems justified. A brief paragraph on the flag could be added to the Nelson article since at present it is linked only from the infobox.- gadfium 05:53, 14 December 2008 (UTC)

 * Generally support retention of separate article. Wikipedia is not paper, and otherwise as per Gadfium. Ingolfson (talk) 23:53, 20 March 2009 (UTC)

 * Seeing that there was no other comment except mine and Gadfium's oppose, I am now removing the merge proposal. Ingolfson (talk) 23:53, 20 March 2009 (UTC)

Jedi census phenomenon and Nelson
According to the 2006 NZ Census, the nelson region has by far the highest number of "jedi" followers per capita. See http://www.jedichurch.org/uploads/4448/files/NZStats2006.pdf and http://www.jedichurch.org/webapps/site/4448/5930/news/news-more.html?newsid=204814. Does that deserve a mention in this article? I'm too clumsy at wikipedia to put one in myself. (No, I'm not a follower, I just happened to stumble on this information). 60.242.34.19 (talk) 06:26, 14 August 2009 (UTC)

The Colonist newspaper
The Colonist newspaper was published in Sydney, from 1835 to 1840, is this the same paper as the The Colonist once published in Nelson, and mentioned in the article? wcrosbie (talk), Melbourne, Australia 08:06, 17 March 2013 (UTC)
 * No, that's a different newspaper. For further information write to the The Archivist, Nelson City Council, Trafalgar Street since theirarchives are currently closed to the public for earthquake strengthening. --2.124.220.128 (talk) 14:25, 16 August 2013 (UTC)
 * Or look at The Colonist (New Zealand newspaper).  Schwede 66  03:30, 29 March 2024 (UTC)

Music
How about mention of the Nelson School of Music ?
 * It's a wiki. If you've got a reliable source (online or offline), write that part and include the source in between some reference tags:  Schwede 66  17:20, 24 November 2014 (UTC)

Recent IP edits
IP did a spot of wikifiddling, adding nonsense to Irredentism and misleading maps on Nelson Province. Added a list of notable "Nelsonians" to this article, checking the list its not that bad but a couple have only a tangential connection to Nelson. I didn't delete the whole lot, only those with a tangential connection. The IP is edit warring them back. About to warn for 3RR but not going to indulge their edit war. Would appreciate other wikipedia editors checking this and reverting if they concur with my assessment. WCM email 00:39, 7 January 2017 (UTC)
 * Did Rutherford live in Nelson full-time while he attended College there, or was he boarding? If the latter, then I would argue that the Brightwater boy shouldn't be in the list.  Schwede 66  01:16, 7 January 2017 (UTC)
 * I'd agree, the criteria for compiling this seems to be fairly tenuous in some cases. WCM email 01:20, 7 January 2017 (UTC)

Centre of New Zealand
Recently I made quite significant changes to the section about the so-called Centre of New Zealand walk, monument, etc.

I also pointed out (but didn't give precise coordinates, or a citation) that an accurately calculated centroid of area puts the geographic centre of NZ (including all islands) in the Big Bush Conservation Area which lies about 10 km north of St Arnaud.

I calculated various geographic centres myself back in 2002. See this link for positions and more details:

https://forums.geocaching.com/GC/index.php?/topic/38916-centre-of-the-mainland/&do=findComment&comment=464562

I've also repeated these calculations more recently, also using different datasets (also higher resolution, available from LINZ), and also using different methods (i.e. using centroid function in QGIS). All of these results are consistent, and the differences are relatively small (as expected). Thus I am very confident of what I have written, but have not yet published the most recently calculated positions anywhere public.

In early 2019 I contacted the Nelson City Council (NCC), LINZ, and GNS and some others, in an attempt to learn exactly what the NCC used as basis for various things they have said on their site about the "Centre of New Zealand". Eventually NCC sent me a draft of an early version of what they had on their website which referenced a 27 June 1962 article in the Nelson Evening Mail. After passing that extra detail to GNS (who have many of the original DSIR records), their staff located a clipping of the original article in their library which I have since made available publicly at:

https://drive.google.com/file/d/1giLDfmjydEA8HMARufmWodgdSZ1zbI9D/view

It is clear (to me at least) that the results calculated by Dr Reilly in 1962 (and also, interestingly, on NZ's first computer!) were not very precise - he estimated the error margins to be about 5 minutes of arc (i.e. more than 9 km in the north/south direction) and my own more recent recalculations using much higher resolution data show that even that was too low. Despite the error margins given for the 1962 calculations, NCC and many others simply quote the position calculated as if it was "exact".

It is not all that difficult to recalculate the results using publicly available data if you have the appropriate expertise using a GIS package, and/or some coding ability. I'm happy to explain in more detail if anybody is interested, but will also try to publish the details in due course. The method I used in 2002 was essentially the same as what Dr Reilly in 1962 did but used DEM (Digital Elevation Model) data where the resolution was 500m squares instead of the very coarse 7.5 minute of arc rectangular blocks that he used. More recently I've used data that was 80m squares, and also the latest shapefiles made available by LINZ.

SeeNoEvil (talk) 02:23, 26 August 2019 (UTC)
 * Good work. But you better get that published as right now, it’s original research (that WP isn’t fond of).  Schwede 66  18:37, 26 August 2019 (UTC)
 * Thanks for that advice Schwede66. I've been looking at what exactly "original research" is, versus "routine calculations" (https://en.wikipedia.org/wiki/Wikipedia:No_original_research#Routine_calculations), and thinking about what I should publish and exactly how. Although I can understand how many might think this kind of calculation is beyond a "routine calculation" it's not that I've invented anything really new - more like just did the calculations again using more accurate and complete data (which is also made available publicly by LINZ, etc.) Any suggestions would be welcome. My vague plan at this stage was to to post something to my blog in a way that would also allow someone else to relatively easily reproduce the calculations I did, and so be able to confirm the results. This would involve sharing some of the code I wrote, and detailing various steps required if using QGIS (for example). SeeNoEvil (talk) 03:06, 28 August 2019 (UTC)

 * Nice piece of work!
 * But do you really mean "...the geographic centre of NZ (including all islands)..." and including all the nine island groups, located in the subtropics and subantarctic, which are part of New Zealand but lie outside of the New Zealand continental shelf or just the "main" three islands (and their offshore islets) included in the original designations of New Ulster, New Munster and New Leinster ?
 * ie have you included the "Area Outside Territorial Authority" together with the Chatham and Solander islands? Surely if you include such outliers as the Bounty and Antipodes islands, the geographical centre (as opposed to the gravitational centre of the land masses of the realm) of New Zealand lies far to the south and east in the great southern ocean? --BushelCandle (talk) 15:06, 27 August 2019 (UTC)

 * Hi BushelCandle. The 1962 newspaper article about the positions calcuated by Ian Reilly says that he didn't include the outlying islands (such as the Chathams) but did include the coastal islands. My own earlier (2002) calculations used a dataset that also only included the three main islands plus smaller coastal islands. In more recent times (earlier in 2019) I've redone the processing using other more recent data sets that also did not include the outlying islands but were 'higher resolution", getting positions that were typically a few hundred metres away from the 2002 results. That kind of difference is consistent with what I would expect from the higher resolution data used. However earlier this year I also learned how to use QGIS (in the process of trying to reproduce what GNS did when they calculated geographic centres for the NZ Extended Continental Shelf, which unearthed another "interesting story") and then calculated the centre of all NZ land (including the outlying islands) using both the NZCS2000 and the NZTM2000 projections using that, using a LINZ sourced shapefile including all. Including those additional outlying islands moves the geographic centre (i.e. centroid of area) a few kilometres south and east as compared to the result obtained when excluding them. Using those different projections again produces slightly different final positions, roughly half a kilometre apart. Excluding the outlying islands produces a result near the northern boundary of of the Big Bush Conservation Area, and including those outlying islands produces a point just inside the same area but further south and quite near the eastern boundary.

 * See the map showing the "entire realm of New Zealand" here: https://en.wikipedia.org/wiki/New_Zealand_outlying_islands

 * The centroid of area is essentially determining the balance point as if it was a two dimensional map balancing on a pin, and with disjoint sections of land (islands!) we also have to imagine the ocean is excluded yet the separate islands are still somehow held in the correct relative positions! Most of the outlying islands are quite small so their effect on the final position is not as great as you may think.

 * SeeNoEvil (talk) 22:37, 27 August 2019 (UTC)

 * This whole conversation is about Original Research no question about it. None of this can get into Wikipedia without it being published indepedently in reliable sources.  I also think the concept of the "centre of NZ" is being taken way to seriously for everyones own good.  This conversation has already gone over the line of not being appropriate for a Wikipedia talk page. Andrewgprout (talk) 04:05, 28 August 2019 (UTC)
 * That's what I guessed. If you are excluding both land masses under water and the water that surrounds them, then you are not calculating the geographical centre but rather the gravitational centre (or centre of mass) of New Zealand's dry land. --BushelCandle (talk) 16:13, 30 August 2019 (UTC)
 * I realise you prefer to use "gravitational centre" and I don't have any particular issue with that terminology in the general case, but reject your assertion that I am "not calculating the geographical centre". To avoid annoying others here, continued at User_Talk:BushelCandle. SeeNoEvil (talk) 23:07, 1 September 2019 (UTC)

Strangely, I've only found this article tonight: 24 April 2019 Dominion Post article "Centre of NZ Debate Fires Up". Is this sufficient to satisfy the "citation needed" tag in the sentence "Recalculating the result with more modern and accurate data shows the geographic centre of New Zealand is approximately 60 km southwest of Nelson, in the Big Bush Conservation Area north of Saint Arnaud, New Zealand"? — Preceding unsigned comment added by SeeNoEvil (talk • contribs) 11:23, 8 September 2019 (UTC)
 * Interesting article - did you co-operate with Clive Gifford? --BushelCandle (talk) 08:32, 13 September 2019 (UTC)
 * Interesting question - does one cooperate with himself? The reason I asked here about the possible use of that article as a citation was exactly because it refers to me, and so I wanted to hear what others thought. I contacted the journalist back in April and he told me later he was going to do a follow-up article but when I searched a few days after that I saw nothing and so assumed he had changed his mind. I only stumbled over it earlier this month. SeeNoEvil (talk) 00:14, 14 September 2019 (UTC)
 * Thank you for clarifying that you are indeed Clive Gifford (I didn't want to be accused of outing you since doxing people is severely frowned on here). Personally I think the citation is fine - especially as you have now declared your connection. --BushelCandle (talk) 10:16, 15 September 2019 (UTC)

Wiki Education assignment: Composition I - Writing Wikipedia
— Assignment last updated by DarthVetter (talk) 13:46, 23 March 2023 (UTC)

license: Creative Commons - Attribution Share-Alike - https://creativecommons.org/licenses/by-sa/4.0/

title: Talk:Nelson, New Zealand


text:
Talk:Kipper

I wonder how long it took for other families to start producing kippers? The Robson firm in Craster are into the fourth generation and are using very old smokehouses.

Yes - the article assumes that the story is true, though I don't know if there is a date attached to it. I wonder if it is generally accepted that the place is Seahouses really did invent kippering?? Nevilley 07:53 Feb 4, 2003 (UTC)

Kippers IS a cultural word
"Kipper's for breakfast" is a stereotypical British saying that I can off the top of my head remember mention by both Super Tram (Breakfast in America), Bart Simpson (Bart of Darkness episode) and I know there are more, just can't think of any. Perhaps someone else can come up with more. Should it have it's own cultural reference section? I'm not an editor, just a point-it-out-'er Fadedroots (talk) 18:06, 27 December 2009 (UTC)
 * "Smoke me a Kipper for breakfast" is a catch phrase of Dave Lister -- The frood talk 23:11, 2 July 2012 (UTC)
 * The precise sentence is "Smoke me a kipper, I'll be back for breakfast." said by Ace Rimmer, not Dave Lister, in the episode "Dimension Jump". MidlandLinda (talk) 20:00, 13 February 2013 (UTC)

kippen
I'm not entirely sure of the Danish origin of Kippen but believe it to be accurate.

Stbalbach 09:12, 25 Jul 2004 (UTC)

Old English origin
The Old English origin of kipper is sourced from the 1911 Encyclopaedia Britannica

Kipper Legends
The origin of kippers is Old English. Old English dates back a thousand years or more. This is established by the 1911 Encylopedia Brittanica entry for kipper (see google, the "k" volume has not been made avilable yet to Wikipedia as of this writing). Since kipper is pre-historic and there is no definitive origin story on record, there is probably more than one kipper origin legend in the world, and they would all be very local in flavour, perhaps helping the merchant or town who created the legend.

The main body of the kipper article should not be clutterd up with all these local legend refrences.. it is confusing and inaccurate. Scholaraly research shows that "kipper" has been around for a long time dateing back a thousand years or more. The legend should either be clearly marked as "false", or it should be moved to a seperate "legends" article. One or the other. I have tried but keep getting my changes set back. Have fun.

 * But actually in its present form, thanks to the additions you have made and the work of other editors, it's pretty good! You get the amusing local legend bit and the rebuttal giving dates and sources, so I think it's the best of both worlds. Thanks and well done. --82.35.17.203 18:53, 31 Jul 2004 (UTC)

Edibility of spawning fish
The article states in at least two places that spawning fish are not edible unless kippered. We here in the Pacific Northwest love to eat many species of fish (mainly the Pacific salmon species) caught on their way to spawn. While salmon certainly can be smoked and/or kippered, it is most commonly eaten without such preservation. Perhaps the article could specify if there are indeed other species which must be kippered in order to be palatable. -- BlueCanoe 01:27, 29 September 2006 (UTC)

 * It's been over two years since I wrote this. I remember my source said it, but I don't remember my source (ie. inline citations are a good thing, even for your own future reference). I thought it was unusual also, I had never heard that before. Perhaps what they meant was, because spawning fish are caught in large numbers in a short period of time they need to be preserved so they remain editable. I suspect that is what is meant here (this is certainly true for indigenous people in the Pacific west coast no?). I will change it. -- Stbalbach 15:53, 29 September 2006 (UTC)

pull/snatch the viscera?
Wetman, do you have a source for this (bold part):

 * The Old English origin of the word has various parallels referring to the process of stripping away the fishes' viscera, such as Icelandic kippa which means "to pull, snatch" and the Danish word kippen which means "to seize, to snatch".

It goes on to say:

 * Similarly, the English kipe denotes a basket used to catch fish.

Wouldn't it make more sense that "to pull, snatch" is the process of catching the fish with a basket during spawning periods when they are schooled up in masses, such as what the English word suggests? I've cleaned many a fish in my day, and never thought of it as pulling or snatching. I could be wrong, and since it seems to contrast with the English kipe definition, I was hoping you could provide a source for the fish cleaning station definition. -- Stbalbach 04:12, 26 October 2006 (UTC)

 * No, the scraping action simply seemed intuitive to me. Revert my insertion id it's astray. --Wetman 04:26, 26 October 2006 (UTC)

Salted and smoked fish
According to this excellent article there are a number of variants on the salted and smoked fish, "the differences lie in the type, combination and duration of the processes." It lists kipper, Yarmouth bloater, buckling, red herring and whitebait. I'm not sure it would make sense to have a separate article for each, would it make sense to have a single article called smoked salted fish or cured fish? -- Stbalbach 02:45, 30 November 2006 (UTC)

 * Found fish curing, smoked fish, salt-cured meat, curing (food preservation), smoking (cooking technique) - probably others. --Stbalbach 12:06, 30 November 2006 (UTC)

My edits
Please see, http://www.fishbase.org/Glossary/Glossary.cfm?TermEnglish=cold%20smoked, just as one example of many places where it is made clear that cold-smoked fish like kippers have to be cooked before being eaten. Perhaps Stbalbach is not familiar with cokking and kitchen techniques. "Kipper snacks" are defined in US food safety law as being pre-cooked so that the consumer can eat them "as is." The distinction is very real, and legal.24.168.4.15 23:10, 6 April 2007 (UTC)

I am confused by Stbalbach's other comments. Kippers are not sushi: sushi (and sashimi, which is actually more often like what I think Stbalbach means to refer to) do use raw fish, but these are extremely fresh, are normally not cured (except for the smoked salmon in American markets, and this smoking process is different from the cold smoking of kippers). Also, nowehere does it say kippers are somehow only legally allowed to be eaten at breakfast - it says that they are often eaten at breakfast, and they are: scrambled eggs may be eaten at any hour of the day, as may cornflakes, but they are most often thought of as breakfast=-type foods, and the sentence is consistent with that in this case. I'm not sure what 'regional preparation" means - the different prep. techniques were not regioanlized, but listed as the most common ways kippers are cooked, in any region. I am not clear why there is such dismissive hostility in the edit comment: nothing added to the article was not true, common knowledge, fairly stated and nothing in it was derogatory or insulting to anyone.24.168.4.15 23:18, 6 April 2007 (UTC)

 * Well, according to out very own Smoking (cooking technique) article, lox is cold smoked. I've personally eaten un-cooked cold smoked herring (it was for supper!). Maybe there is some recent English law about it for food safety reasons, but that's a separate issue, the world is bigger than just the UK and the US, people have been eating uncooked cold smoked fish since time immortal. As for breakfast, again, people do things in lots of ways, my Korean friends family eat hamburgers for breakfast, and I'm sure 300 years ago peasants didn't worry about eating fish for breakfast when that was all they had to eat anyway. What your describing is a very British, very recent cultural norm. -- Stbalbach 01:23, 7 April 2007 (UTC)

adamantine nastyness shown in these edits. -- you need to stop these personal attacks. There is no "nastyness". If you can't deal with working through content issues on the talk page without making personal attacks then we have a bigger problem to deal with. Name calling is unacceptable. -- Stbalbach 01:34, 7 April 2007 (UTC)

I don't understand the admantine nastyness. The name-calling has been from your side, all about how I don't know what I'm talking about, and I'm Uk-centric (I'm American), and etc. etc. First, my edits were neither British nor American based (I am an American). Second, the presence of botulism, listeria, and parasites in cold-smoked fish are extremely well-attested and widely known in the industry and government, and have been known for many years. Third, lox is not JUST cold-smoked - it is first salt-cured in a way which deals with a lot of these issues. Eating uncooked, cold-smoked kippers exposes someone to potential botulism poisoning. Nobody says one cannot have kippers for supper, the article as I edited said very specifically that yes, in the Uk, yes, it is a common breakfast food. I don't understand why that has generated such energetic hatred from you, particularly since you seem to bounce back and forth: you want the artricle edited according to YOUIR personal experinces ("Well, I have eaten such and such for dinner") but accuse me of basing it on MY personal experiences when I am actually quoting common government and industry standards. I'm sure you've eaten fish, but you really seem unfamiliar with how they are prepared and cooked. Perhaps you should back off a bit and leave that portion of the article to those who know more in that particular field.24.168.4.15 01:42, 7 April 2007 (UTC)

Please confer: http://www.norfolkkipperhouse.co.uk/page4.htm ; a private UK fish expert http://www.agmkt.state.ny.us/FS/industry/fishprocess.html ; a US government note http://www.defra.gov.uk/foodrin/foodname/UKingdom/arbsm.htm ; a UK government note ftp://ftp.fao.org/docrep/fao/007/y5394e/y5394e00.pdf ; a UN FAO note, which covers the whole world http://books.google.com/books?id=2LyckiERaYMC&pg=PA110&lpg=PA110&dq=cold+smoked+kippers+safety&source=web&ots=yfCGSv-DH7&sig=Bi-QZZCDhjcAfY3isZ2AcuxuXFo#PPA109,M1 ; a scholarly treatise on the subject http://www.warwickshire.gov.uk/corporate/SmallBus.nsf/20b1663bdac8d4e180256ca700457904/4f96121bb1f3522780256e2f0062c01b?OpenDocument ; labelling requirements related to cold-smoked fish needing to be cooked How much evidence is necessary before people will simply leave this topic alone and stop, I don't know, reverting it based on medieval practices or something?24.168.4.15 02:06, 7 April 2007 (UTC)

It's difficult and unpleasant to work with someone who continues to make personal attacks like "energetic hatred", "admantine nastyness", "insist on having it his own way" and even accused me of calling you names (where?!). It seems pretty obvious we can't work this out on the talk page, I will ask for an administrator to review the edit history and provide some moderation. -- Stbalbach 22:53, 7 April 2007 (UTC)

Every edit has been 100 percent factual, I've even supplied numerous official and professional websites backing it up, and yes, Stbalbach, using a dismissive tone and constant reverting of edits simply because they aren't yours, making denigrating comments about the worth of others edits and stuff is very unprofessional and "nasty" on your part. I didn't name-call, I pointed out that you began this by reverting with constant belittling comments - that's not "incivility," it's pointing out your own incivility. Reverting factually accurate edits because you don't like the person making them, or, from your tone, you aren't happy with people trespassing on what you seem to regard as your page is not helpful to anyone. For instance, if you can factually refute the fact that the UK, US and Euro-union governments, as well as expert fishmongers and chefs all say one literally takes one's life in one's hands by eating uncooked cold-smoked fish (as exemplified by the numerous citations above), then you have some call to keep reverting, but to base your reverts on the fact that you claim to have eaten raw kippers and lived to tell the tale is the very "personal experience" you high-handedly and dismissively originally labelled my edits. People in ancient times probably ate raw chicken, people in the Middle Ages probably ate raw eggs, steak tartare is raw beef and long considered a delicacy, but advising someone to eat these today is begging for salmonella poisoning. Your reverts have shown that you really don't know anything about cooking -- OK, there's no law that says you have to, but on the other hand how would you stand for somebody re-editing all of your Anglo-Saxon pages on the basis of once having had to read Beowulf for high school English class? You really don't know what you're talking about here, and that's fine -- nobody is an expert in everything and there is no shame in walking away from a page and saying to yourself, "gee, I guess i didn't know what I was talking about, and now I've learned something new from somebody who does," but to constantly adamantly revert based on nothing, and particularly certain edits which really do put people's health at risk from thinks like botulinum and listeria, is completely counterproductive. It's a goddam entry on a type of edible fish -- why are you clinging to it like someone is attacking your religion?24.168.4.15 18:55, 9 April 2007 (UTC)

 * Please stop reverting the edits. Place your suitable sources for the information concerned below this line and settle to a resolution. Also be aware of the 3RR rule. Thank you.-- KZ Talk • Contribs 22:53, 9 April 2007 (UTC)

So, you filed your comments without bothering to read any of the talk? You demand sourcing, but if you had read the talk you would see that I clearly already provided extensive sourcing, and that what Stbalbach keeps insisting on with absolutely no sourcing at all, is simply wrong. Why must all my sourcing now be repeated "below the line"? Why is pointing out the high-handed and dismissive language of Stbalbach, which he started right from the beginning, and continues, worthy of a stern warning against me, but he is permitted to keep reverting my absolutely factually backed-up edits with nasty comments, and that's OK? The material is simply, factually untrue, even as currently edited by you, and is in fact a health hazard, but to preserve Stbalbach's hurt feelings I have to simple stop editing the page? I'm bewildered. I started making edits to a page I actually know quite a bit about professionally, with perfectly solid 3rd part sources, and I was taking all this Wikipedia philosophy seriously, and yet I am treated like an incompetent leper. Consider it "incivil" of me, but man oh man, does Wiki make people feel like this is all about some in-crowd and a lot of cliques of editors and administrators, and nothing to do with accuracy or comptetence in the field. I've read a lot of criticism of Wikipedia in the press and online, and I thought it was all crazy, but geez, you try to make an article about food less harmful to people's health and because some Medieval historian has suddenly made kippers his religion, having apparently never set foot in a kitchen, you get slammed by the "government" of Wikipedia. What a way to completely turn off anybody with any actual expertise, and no agenda or "cause" to push, from ever wanting to get involved with Wikipedia.24.168.4.15 23:47, 9 April 2007 (UTC)
 * I've reverted back to your version of the edits, so please regain your patience. I asked Stbalbach to keep it this way until this dispute is over. You have not been treated as a "incompetent leper", as stated, but I apologize in advance if you feel that you have been. -- KZ Talk • Contribs 00:11, 10 April 2007 (UTC)

Evidence by User:24.168.4.15

 * Please see, http://www.fishbase.org/Glossary/Glossary.cfm?TermEnglish=cold%20smoked, just as one example of many places where it is made clear that cold-smoked fish like kippers have to be cooked before being eaten. Perhaps Stbalbach is not familiar with cokking and kitchen techniques. "Kipper snacks" are defined in US food safety law as being pre-cooked so that the consumer can eat them "as is." The distinction is very real, and legal.24.168.4.15 23:10, 6 April 2007 (UTC)
 * http://www.norfolkkipperhouse.co.uk/page4.htm ; a private UK fish expert
 * http://www.agmkt.state.ny.us/FS/industry/fishprocess.html ; a US government note
 * http://www.defra.gov.uk/foodrin/foodname/UKingdom/arbsm.htm ; a UK government note
 * ftp://ftp.fao.org/docrep/fao/007/y5394e/y5394e00.pdf ; a UN FAO note, which covers the whole world
 * http://books.google.com/books?id=2LyckiERaYMC&pg=PA110&lpg=PA110&dq=cold+smoked+kippers+safety&source=web&ots=yfCGSv-DH7&sig=Bi-QZZCDhjcAfY3isZ2AcuxuXFo#PPA109,M1 a scholarly treatise on the subject
 * http://www.warwickshire.gov.uk/corporate/SmallBus.nsf/20b1663bdac8d4e180256ca700457904/4f96121bb1f3522780256e2f0062c01b?OpenDocument

Forget it. This has opened my eyes to what Wikipedia truly is when it comes to a reliable information source. The reputation and the negative press Wikipedia has gotten I'm begeining to think is richly deserved. Stbalbach can do whatever he wants to the article, and so can you. This is my last visit in any way, shape or form to Wikipedia since clearly I won't be permitted to contribute and whatever information I can offer is clearly unwanted. I think you and Stbalbach better hope that liability law never allows somebody who gets hospitalized or worse with clostridium botulinum to sue you and Stbalbach because of what was presented as reliable on Wikipedia. I don't have the energy to fight for what is blackletter accepted uncontroversial information anywhere else in the world. Have a nice day.24.168.4.15 00:37, 10 April 2007 (UTC)

I'm really kind of laughing over this because nothing I did in my latest edit changed anything of substance to what the anon editor wrote. Everything was kept. All I did was move it out of the Lead Section, per the guidelines at WP:LEAD into the body of the article - many new users mistakingly believe that the more "important" information is, the higher up towards to top of the article is goes, which is not the case, see WP:LEAD. Also, there are different ways to prepare Kipper, this article covers not only modern smoking techniques (used for flavor purposes) but the traditional heavy salting and smoking (used for preservation), so I added a qualifier to that end. These two things: moving content to the body of the article and 2) adding a qualifier on the different ways of preservation. Comments? -- Stbalbach 14:25, 10 April 2007 (UTC)

 * Well it doesn't really matter now because it isn't really a dispute anymore. The ip has recently quit Wikipedia. -- KZ Talk • Contribs 07:06, 11 April 2007 (UTC)

Red herrings?
Is this for real? The article on red herring makes no mention of this definition of red herring:

"A red herring is a whole unsplit fish. Red herring can be served cold, sliced thinly across the body with new bread and butter or a salad as a starter."

130.119.248.12 14:25, 3 October 2007 (UTC)

Merge
I support the merge with Kipper season. Brandonrush (talk) 16:27, 22 December 2007 (UTC)
 * As there were no objections, I carried out this merge (really more of a redirect - there was no content in the other article which wasn't already in this one). Terraxos (talk) 15:28, 8 January 2008 (UTC)

ad
I remeoved the "The John West brand of canned kipper fillets is a commonly found item in stores or supermarket sections devoted to imported British foodstuffs." because it is nothing more than an ad. Kipper smacks of various brands are available at most US supermakets in the canned fish section and British foods in the British food section. 71.233.97.113 (talk) 20:51, 12 June 2008 (UTC)

"Time immemorial"
Under Origin, it says:
 * The exact origin of kippers is unknown, though fish have been slit, gutted and smoked since time immemorial.

While this is lovely, poetic, and most likely accurate, the citation provided doesn't really support "time immemorial," since the cite references Lewis and Clark, which is 18th century. Also, it doesn't actually provide a REFERENCE, just says that L&C saw Native Americans smoking salmon, without saying how we know they saw it. -- DrGaellon (talk | contribs) 13:08, 26 March 2010 (UTC)

When is a kipper not a kipper?
Supermarkets (er, co-op, tesco ..) have recently taken to selling a disgusting boil-in the-bag product, usually called "kipper fillets" that bears little resemblance to the real thing. When you read deep into the label, it apparently contains "responsibly sourced" herring (95%), salt and a little butter (2.5%), an unspecified 2.5%. and the lurid yellow colour comes from annatto, a known allergen. I shall have to undertake further research to find out what further travesties have been committed in the name of profits.

Is there any precedence for these things being legally presented as kippers? Or is the term un-protected, so you can sell any rubbish and call it that?

A kipper by any other name.... —Preceding unsigned comment added by Memethuzla (talk • contribs) 13:10, 5 May 2011 (UTC)
 * Nothing recent about this, if I recollect correctly supermarkets were selling the travesty that  are boil in the bag kippers when I was a kid in the 1970's  -- The frood talk 23:15, 2 July 2012 (UTC)

Merger proposal: Orange kipper
There is a degree of overlap between this article and Orange kipper, so I'm wondering if Orange kipper should be merged into this article. -- The frood talk 15:05, 2 July 2012 (UTC)
 * Support merge, due to significant article overlap. JoeSperrazza (talk) 19:23, 2 July 2012 (UTC)
 * Support merge --Epipelagic (talk) 21:44, 2 July 2012 (UTC)
 * Support With a redirect from Orange kipper Mcewan (talk) 15:27, 3 July 2012 (UTC)

"He eteþ no ffyssh But heryng red"
The section on Colouring has a quote that looks like vandalism to me. Is this the actual quote or did someone just make the quote look stupid as an act of vandalism? Qwertyxp2000 (talk | contribs) 08:05, 2 March 2016 (UTC)
 * Þou knowest not Middel Englissh? It is writyng moste propre. Þer be no maner or werke of meschief in þatt whych is wrote. Ian.thomson (talk) 05:44, 3 March 2016 (UTC)
 * You mean this is just a Middle English quote? Qwertyxp2000 (talk | contribs) 06:13, 3 March 2016 (UTC)
 * It is a relevant quote in Middle English, yes. Ian.thomson (talk) 06:45, 3 March 2016 (UTC)
 * Wow, did not notice until discussion. This is why discussions are so valuable. They prevent edit-wars and content disputes. Qwertyxp2000 (talk | contribs) 09:06, 4 March 2016 (UTC)
 * I'm mostly glad that this worked out, because a side of me I rarely allow anywhere near Wikipedia was ready to edit war over the quote using only Middle English edit summaries and discussion. Ian.thomson (talk) 09:27, 4 March 2016 (UTC)

Peel produces thousands of somethings
The article reads, "Kippers produced in the Isle of Man are exported around the world.[13] Thousands are produced annually in the town of Peel ..."

OK. Thousands of tons (or tonnes)? Of fish? Of cans? Of kilograms? Of barrels? I have no idea what this sentence means. IAmNitpicking (talk) 13:23, 25 July 2016 (UTC)

External links modified
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 * Added archive https://web.archive.org/web/20080704112754/http://www.mallaigheritage.org.uk/exhibit/mallaig.htm to http://www.mallaigheritage.org.uk/exhibit/mallaig.htm

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Kippers are not a common breakfast food in the United Kingdom
I am British and have never in my life heard of someone eating kippers for breakfast. I doubt if the average British person these days knows what kippers are, let alone eats them regularly! The reference given for this claim in the article is a link to a fanciful Guardian recipe by posh-boy Hugh Fearnley-Whittingstall—hardly representative of the common breakfast. Perhaps kippers were commonly eaten a hundred years ago, but certainly not any more. Frankly, the notion that kippers remain a common breakfast food in the United Kingdom is a gross stereotype that I'm surprised to see supported by Wikipedia. Claude Chabrol (talk) 13:40, 25 July 2022 (UTC)
 * What nonsense! Good hotels and most supermarkets sell them, and they are normally only ever eaten at breakfast. I have them, not all the time, but certainly "commonly". The cooked breakfast generally has greatly declined in all forms, but the statement remains correct. Johnbod (talk) 13:46, 25 July 2022 (UTC)
 * Agreed. I'd go further and say that every major supermarket chain sells them.

 * the notion that kippers remain a common breakfast food in the United Kingdom is a gross stereotype - that's not what the article currently states though. It says "kippers are most commonly eaten for breakfast" and "kippers are often served for breakfast, and much less often at lunch or dinner", i.e. someone eating kippers would normally eat them for breakfast. There's no claim that they are a common breakfast food. Subtle but important difference. Barry Wom (talk) 14:01, 25 July 2022 (UTC)

Old English
Have modified the Old English etymology; /k/ is not a letter in old English; kipian is not in the corpus. 121.209.139.246 (talk) 06:03, 11 May 2023 (UTC)

preservation of "surplus" fish
the article talks about "the preservation of surplus fish": before the advent of refrigeration, the vast bulk of fish caught were cured. If you seined a batch of fish today and wanted to eat them next week, they needed to be preserved. fishing boats frequently salted them right away before returning to port. So, technically sure, the fish were "surplus", but that was the goal, to catch surplus fish, just as you harvest surplus vegetables during harvest season, i.e. it was just catching fish, no surplus involved 2603:8001:D3F0:87E0:0:0:0:1DF6 (talk) 10:14, 10 January 2024 (UTC)

title: Talk:Kipper


text:
User:Nanshu

 * First edit: January 2003

title: User:Nanshu


text:
Kitengela

Kitengela is a municipality in the Kajiado County of Kenya, located 34 Kilometres south of the capital Nairobi, forming part of the greater Metropolitan Area. Kitengela began as The Kitengela group ranch, made up of 18,292 ha and 214 registered members which was subdivided in 1988 in efforts by the Government to encourage private land ownership in pastoral systems, with the aim of intensifying and commercializing livestock production. After subdivision of the group ranch, land fragmentation and sales have continued at a steady and escalating pace. The human population within the Kitengela area has more than doubled in the last 10 years, from 6548 in 1989 to 17,347 in 1999 to 58,167 in 2009. There is also a town named Kitengela in the area.

Close to Nairobi National Park is also the Kitengela Game Conservation Area populated with buffalo, Masai giraffe, eastern black rhino, Common eland, impala, Grant's and Thomson's gazelle, common waterbuck and Defassa waterbuck, hippopotamus, common warthog, olive baboon, monkeys and the attendant carnivores – lion, spotted hyena, cheetah, side-striped and black-backed jackals, African golden wolves, bat-eared fox and smaller carnivores.

The diversity of species is decreasing in the Kitengela area adjacent to the Nairobi National Park, where land-uses not compatible with wildlife are increasing.

Kitengela town
Kitengela is a town in Kajiado County just 30 km south of Nairobi and is part of the Nairobi Metropolitan Area. Kitengela is one of the fastest growing urban areas of Kenya according to census data of 2019, having tripled in population inflows since 2009. It has an urban population of 154,436 people.

Kitengela is close to Athi River town in Machakos County in the former Eastern Province, while Kitengela belongs to Kajiado County in the former Rift Valley Province. Kitengela is growing quickly and is expanding with a huge influx of middle class Nairobians who have built lovely gated communities and businesses in an unprecedented construction boom, thanks to the affordable land compared to Nairobi city as well as availability of 5 cement companies and growing infrastructural amenities. Residents describe Kitengela as "having the best of both worlds," given its close proximity to Nairobi but easy-going slow-paced rural feel, as well as the friendly, collaborative nature of the resident population.

Kitengela is famous for nyama choma (roast meat) – a Kenyan delicacy. The town has a wide variety of restaurants that serve this delicacy. Some of the most famous ones include the famous Yukos, Enkare, Arusha Meat Den and numerous more.

Kitengela has a wide variety of financial institutions and saccos (savings and credit cooperatives) that have flooded the town to finance the construction boom as well as cater to the soaring middle class population. It also has seen a boom in posh hotels, clubs and other entertainment facilities. In recent times Kitengela has developed a reputation for new, unique cutting-edge entertainment facilities such as Charlie's Bistro, Sparrows, Quiver, Guru, and 034, a 5 star club nestled in an airplane have sprung up in the town – a first for Kenya.

As Kitengela's middle class population has boomed, so has its wide variety of high end schools and universities to cater to the children of the middle classes. Some of the schools include Kitengela International Schools, Acacia Crest, Chuna Preparatory, Orchard Schools, Nova Pioneer Kitengela and numerous more. Some of the universities and colleges include KCA University Kitengela campus, Kitengela Institute of Management Studies, KAG East University, East African University, RAF International University among others.

Kitengela's gated communities for the middle classes include Chuna, Milimani, Royal Gates, New Valley, Muigai Prestige, New World Gardens, Safaricom 1 & 2 estates, Police Sacco Estate, EPZ estate, Fountain View, Riverside, Upper Valley, Kenpipe Gardens, Acacia and many more. These estates have seen an unprecedented boom due to the fact that most of them are controlled, not allowing unsightly flats or small businesses/kiosks within their gated walls. Chuna Estate, Royal Finesse and Royal Gates are considered among the best organised of them but many more are coming up each year. With the construction and completion of Isinya pipeline road, as well as the ongoing construction of the Mlolongo to Waiyaki Way expressway, as well as Konza City Metropolis nearby, Kitengela is poised to experience even more growth and development.

Kitengela is served by Jomo Kenyatta International Airport, Athi River SGR station as well as a future commuter rail station that is currently under construction that will connect commuters to Nairobi CBD.

title: Kitengela


text:
Lime kiln

A lime kiln is a kiln used for the calcination of limestone (calcium carbonate) to produce the form of lime called quicklime (calcium oxide). The chemical equation for this reaction is

 * CaCO3 + heat → CaO + CO2

This reaction can take place at anywhere above 840 C, but is generally considered to occur at 900 C (at which temperature the partial pressure of CO2 is 1 atmosphere), but a temperature around 1000 C (at which temperature the partial pressure of CO2 is 3.8 atmospheres ) is usually used to make the reaction proceed quickly. Excessive temperature is avoided because it produces unreactive, "dead-burned" lime.

Slaked lime (calcium hydroxide) can be formed by mixing quicklime with water.

In plaster, proto-pottery, and mortar
Because it is so readily made by heating limestone, lime must have been known from the earliest times, and all the early civilizations used it in building mortars and as a stabilizer in mud renders and floors. According to finds at 'Ain Ghazal in Jordan, Yiftahel in Israel, and Abu Hureyra in Syria dating to 7500–6000 BCE, the earliest use of lime was mostly as a binder on floors and in plaster for coating walls. This use of plaster may in turn have led to the development of proto-pottery, made from lime and ash. In mortar, the oldest binder was mud. According to finds at Catal Hüyük in Turkey, mud was soon followed by clay, and then by lime in the 6th millennium BCE.

Lime use in agriculture and coal
Knowledge of its value in agriculture is also ancient, but agricultural use only became widely possible when the use of coal made it cheap in the coalfields in the late 13th century, and an account of agricultural use was given in 1523. The earliest descriptions of lime kilns differ little from those used for small-scale manufacture a century ago. Because land transportation of minerals like limestone and coal was difficult in the pre-industrial era, they were distributed by sea, and lime was most often manufactured at small coastal ports. Many preserved kilns are still to be seen on quaysides around the coasts of Britain.

Types of kilns

Permanent lime kilns fall into two broad categories: "flare kilns" also known as "intermittent" or "periodic" kilns; and "draw kilns" also known as "perpetual" or "running" kilns. In a flare kiln, a bottom layer of coal was built up and the kiln above filled solely with chalk. The fire was alight for several days, and then the entire kiln was emptied of the lime.

In a draw kiln, usually a stone structure, the chalk or limestone was layered with wood, coal or coke and lit. As it burnt through, lime was extracted from the bottom of the kiln, through the draw hole. Further layers of stone and fuel were added to the top.

Early kilns
The common feature of early kilns was an egg-cup shaped burning chamber, with an air inlet at the base (the "eye"), constructed of brick. Limestone was crushed (often by hand) to fairly uniform 20 - 60 mm lumps – fine stone was rejected. Successive dome-shaped layers of limestone and wood or coal were built up in the kiln on grate bars across the eye. When loading was complete, the kiln was kindled at the bottom, and the fire gradually spread upwards through the charge. When burnt through, the lime was cooled and raked out through the base. Fine ash dropped out and was rejected with the "riddlings".

Only lump stone could be used, because the charge needed to "breathe" during firing. This also limited the size of kilns and explains why kilns were all much the same size. Above a certain diameter, the half-burned charge would be likely to collapse under its own weight, extinguishing the fire. So kilns always made 25–30 tonnes of lime in a batch. Typically the kiln took a day to load, three days to fire, two days to cool and a day to unload, so a one-week turnaround was normal. The degree of burning was controlled by trial and error from batch to batch by varying the amount of fuel used. Because there were large temperature differences between the center of the charge and the material close to the wall, a mixture of underburned (i.e. high loss on ignition), well-burned and dead-burned lime was normally produced. Typical fuel efficiency was low, with 0.5 tonnes or more of coal being used per tonne of finished lime (15 MJ/kg).

Industrial scale production
Lime production was sometimes carried out on an industrial scale. One example at Annery in North Devon, England, near Great Torrington, was made up of three kilns grouped together in an 'L' shape and was situated beside the Torrington canal and the River Torridge to bring in the limestone and coal, and to transport away the calcined lime in the days before properly metalled roads existed.

Sets of seven kilns were common. A loading gang and an unloading gang would work the kilns in rotation through the week.

A rarely used kiln was known as a "lazy kiln".

Australia
In the late 19th and early 20th centuries the town of Waratah in Gippsland, Victoria, Australia produced a majority of the quicklime used in the city of Melbourne as well as around other parts of Gippsland. The town, now called Walkerville, was set on an isolated part of the Victorian coastline and exported the lime by ship. When this became unprofitable in 1926 the kilns were shut down. The present-day area, though having no town amenities as such, markets itself as a tourist destination. The ruins of the lime kilns can still be seen today.

United Kingdom
The large kiln at Crindledykes near Haydon Bridge, Northumbria, was one of more than 300 in the county. It was unique to the area in having four draw arches to a single pot. As production was cut back, the two side arches were blocked up, but were restored in 1989 by English Heritage.

The development of the national rail network made the local small-scale kilns increasingly unprofitable, and they gradually died out through the 19th century. They were replaced by larger industrial plants. At the same time, new uses for lime in the chemical, steel and sugar industries led to large-scale plants. These also saw the development of more efficient kilns.

A lime kiln erected at Dudley, West Midlands (formerly Worcestershire) in 1842 survives as part of the Black Country Living Museum which opened in 1976, although the kilns were last used during the 1920s. It is now among the last in a region which was dominated by coalmining and limestone mining for generations until the 1960s.

Shaft kilns
The theoretical heat (the standard enthalpy) of reaction required to make high-calcium lime is around 3.15 MJ per kg of lime, so the batch kilns were only around 20% efficient. The key to development in efficiency was the invention of continuous kilns, avoiding the wasteful heat-up and cool-down cycles of the batch kilns. The first were simple shaft kilns, similar in construction to blast furnaces. These are counter-current shaft kilns. Modern variants include regenerative and annular kilns. Output is usually in the range 100–500 tonnes per day.

Counter-current shaft kilns
The fuel is injected part-way up the shaft, producing maximum temperature at this point. The fresh feed fed in at the top is first dried then heated to 800 °C, where de-carbonation begins, and proceeds progressively faster as the temperature rises. Below the burner, the hot lime transfers heat to, and is cooled by, the combustion air. A mechanical grate withdraws the lime at the bottom. A fan draws the gases through the kiln, and the level in the kiln is kept constant by adding feed through an airlock. As with batch kilns, only large, graded stone can be used, in order to ensure uniform gas-flows through the charge. The degree of burning can be adjusted by changing the rate of withdrawal of lime. Heat consumption as low as 4 MJ/kg is possible, but 4.5 to 5 MJ/kg is more typical. Due to temperature peak at the burners up to 1200 °C in a shaft kiln conditions are ideal to produce medium and hard burned lime.

Regenerative kilns
These typically consist of a pair of shafts, operated alternately. First, when shaft A is the "primary" and B the "secondary" shaft, the combustion air is added from the top of shaft A, while fuel somewhat below via burner lances. The flame is top-bottom. The hot gases pass downward, cross to shaft B via the so-called "channel" and pass upward to exhaust of shaft B. At same time in both shafts cooling air is added from the bottom to cool the lime and to make exhaust of gases via the bottom of the kiln impossible via maintaining always a positive pressure. The combustion air and cooling air leave the kiln jointly via exhaust on top of shaft B, preheating the stone. The direction of flow is reversed periodically (typically 5–10 times per hour) shaft A and B changing the role of "primary" and "secondary" shaft. The kiln has three zones: preheating zone on the top, burning zone in the middle, and cooling zone close to the bottom. The cycling produces a long burning zone of constant, relatively low temperature (around 950 °C) that is ideal for the production of high quality soft burned reactive lime. With exhaust gas temperatures as low as 120 °C and lime temperature at kiln outlet in 80 °C range the heat loss of the regenerative kiln is minimal, fuel consumption is as low as 3.6 MJ/kg. Due to these features the regenerative kilns are today mainstream technology under conditions of substantial fuel costs. Regenerative kilns are built with 150 to 800 t/day output, 300 to 450 being typical.

Annular kilns
These contain a concentric internal cylinder. This gathers pre-heated air from the cooling zone, which is then used to pressurize the middle annular zone of the kiln. Air spreading outward from the pressurized zone causes counter-current flow upwards, and co-current flow downwards. This again produces a long, relatively cool calcining zone. Fuel consumption is in 4 to 4.5 MJ/kg range and the lime is typically medium burned.

Rotary kilns
Rotary kilns started to be used for lime manufacture at the start of the 20th century and now account for a large proportion of new installations if energy costs are less important. The early use of simple rotary kilns had the advantages that a much wider range of limestone size could be used, from fines upwards, and undesirable elements such as sulfur can be removed. On the other hand, fuel consumption was relatively high because of poor heat exchange compared with shaft kilns, leading to excessive heat loss in exhaust gases. Old fashioned "long" rotary kilns operate at 7 to 10 MJ/kg. Modern installations partially overcome this disadvantage by adding a preheater, which has the same good solids/gas contact as a shaft kiln, but fuel consumption is still somewhat higher, typically in range of 4.5 to 6 MJ/kg. In the design shown, a circle of shafts (typically 8–15) is arranged around the kiln riser duct. Hot limestone is discharged from the shafts in sequence, by the action of a hydraulic "pusher plate". Kilns of 1000 tonnes per day output are typical. The rotary kiln is the most flexible of any lime kilns able to produce soft, medium, or hard burned as well as dead-burned lime or dolime.

Gas cleaning
All the above kiln designs produce exhaust gas that carries an appreciable amount of dust. Lime dust is particularly corrosive. Equipment is installed to trap this dust, typically in the form of electrostatic precipitators or bag filters. The dust usually contains a high concentration of elements such as alkali metals, halogens and sulfur.

Carbon dioxide emissions
The lime industry is a significant carbon dioxide emitter. The manufacture of one tonne of calcium oxide involves decomposing calcium carbonate, with the formation of 785 kg of CO2 in some applications, such as when used as mortar; this CO2 is later re-absorbed as the mortar goes off.

If the heat supplied to form the lime (3.75 MJ/kg in an efficient kiln) is obtained by burning fossil fuel it will release CO2: in the case of coal fuel 295 kg/t; in the case of natural gas fuel 206 kg/t. The electric power consumption of an efficient plant is around 20 kWh per tonne of lime. This additional input is the equivalent of around 20 kg CO2 per ton if the electricity is coal-generated. Thus, total emission may be around 1 tonne of CO2 for every tonne of lime even in efficient industrial plants, but is typically 1.3 t/t. However, if the source of heat energy used in its manufacture is a fully renewable power source, such as solar, wind, hydro or even nuclear; there may be no net emission of CO2 from the calcination process. Less energy is required in production per weight than portland cement, primarily because a lower temperature is required.

title: Lime kiln


text:
Talk:Johnny Rotten

John Lydon has been known as such since 1978, when he declared his Johnny Rotten persona to be dead after the demise of the Sex pistols... Certainly all of his work since 1979, eg with Pil, Leftfield, etc, has been produced under the name of John Lydon- shouldn't the redirect be the other way around in this case??? quercus robur 11:04 Feb 2, 2003 (UTC)

title: Talk:Johnny Rotten


text:
Talk:E-numbers

List of food additives seems to already cover whats in list of e numbers, so maybe the e numbers list should go? It might be nice to add the potential health concerns into the already established list though... I'll leave it to a third party to decide whats appropriate as I'm probably too POV on this issue... quercus robur 11:11 Feb 2, 2003 (UTC)

Urg just realised we've already got a substantial page on the subject at E number, which includes a link to a THIRD list of additives!!! Looks like some tidying up and merging is required!!! quercus robur 11:15 Feb 2, 2003 (UTC)

title: Talk:E-numbers