Y El Rayess

C Albasi

P Bacchin

P Taillandier

J Raynal

M Mietton- Peuchot

A Devatine

IMPACT OF THE PHYSICO-CHEMISTRY OF THE WINE ON MEMBRANE FILTRATION PERFORMANCE

Keywords: microfiltration membrane, polyphenols, proteins, yeast extract, fouling, wine

During the process of wine making, operation of cross-flow microfiltration allows a one-step clarification and sterilization of wine, with lower waste compared to the conventional processes of clarification and sterilization. Indeed, these processes are sources of voluminous waste (earth, Kieselguhr, additives), when discharges are becoming more and more restricted by environmental and health rules. Nevertheless, cross-flow microfiltration of wine presents a major drawback: membrane fouling causes a significant decrease in the flow rates, due to excessive retention of some wine components which could lead ultimately to the alteration of the quality of wine. The aim of this work was to study the impact of some specific wine components (phenolic compounds and yeast extract), as well as some physico-chemical parameters (pH) in regard to membrane fouling. Studies were performed using one red wine and synthetic wines, using cellulose acetate membranes (0.2 μm) operated in the dead-end mode under 2 bar pressure. The simultaneous presence of the both species of phenolic compounds (anthocyanins and tannins) in the synthetic wine was shown to be the main cause of fouling, whereas the presence of one specie leads only to standard blocking type behavior. An important decrease in the flow rates was also observed when yeast extract was added to the liquid. This yeast extract was shown to contain 300 mg/g of proteins and to be free of mannoproteins. The influence of these proteins on fouling was demonstrated while pre-treating the synthetic wine with bentonite, which was able to adsorb proteins, and in this case, no fouling was observed. It was also shown that, when decreasing the pH, the flow rate was enhanced. For all experiments, a fouling index or cake specific resistance, according to the type of fouling, was calculated in order to be used as a reference to estimate the filterability of a given wine, according to its composition in some targeted molecules. Finally, the experiments of the actual red wine exhibited complete rapid fouling of the membrane, probably due to the presence of high concentration of phenolic compounds.

INTRODUCTION

The crude wine, after fermentations (alcoholic and malolactic), is a complex medium containing many different compounds in solution (small molecules such as organic acids, salts, glycosides, phenolic compounds,…), components of colloidal size (ranging between 1 nm and until a few hundreds of nm: polysaccharides, polymerized phenolic compounds and proteins) and particles (molecular aggregates, micro-organisms, residues of vegetable and microbial cells, crystals of potassium hydrogenotartrate,…) [START_REF] Czekaj | Membrane fouling during microfiltration of fermented beverages[END_REF][START_REF] Vernhet | Contribution to the understanding of fouling build up during microfiltration of wines[END_REF]. However, strict qualitative and healthy specifications are established by the distributors: absence of haze, brightness, microbiological stability, tartaric stability, low oxygen content…

To answer these requirements, the wine makers are used to implement successive solid-liquid separation using traditional technologies such as centrifugation, filtration on plates, diatomaceous earth filtration and the use of exogenic additives. However, restrictions for environment and health preservation lead the viticulture sector to look for alternative techniques to traditional filtrations: crossflow microfiltration could represent this alternative. Indeed, this technology can substitute a one step procedure to the conventional processes which imply several filtration steps on diatomaceous earth previous to the final microbial stabilization obtained by dead end filtration on membranes [START_REF] Czekaj | Membrane fouling during microfiltration of fermented beverages[END_REF][START_REF] Vernhet | Contribution to the understanding of fouling build up during microfiltration of wines[END_REF]. In addition to a great simplification of the wine processing line, cross-flow microfiltration offers a number of additional advantages such as elimination of earth use and its associated environmental problems as well as the combination of clarification, stabilization and sterile filtration in one single continuous operation [START_REF] Moutounet | Application des membranes dans la filière oenologique[END_REF][START_REF] Grangeaon | Innovations dans la microfiltration des vins : membranes et procédés[END_REF].

Unfortunately, the development of cross-flow microfiltration in wine industry is still hampered by the occurrence of significant fouling phenomena upon the microfiltration membranes. This has caused difficulties in obtaining an economical flux rate, as well as good product quality [START_REF] Moutounet | Application des membranes dans la filière oenologique[END_REF][START_REF] Grangeaon | Innovations dans la microfiltration des vins : membranes et procédés[END_REF].

Membrane fouling during cross-flow microfiltration of biological fluids results from a complex interaction between macromolecular adsorption or deposition, internal fouling and cake formation by the retained species [START_REF] Vernhet | Contribution to the understanding of fouling build up during microfiltration of wines[END_REF][START_REF] Belfort | The behavior of suspensions and macromolecular solutions in crossflow microfiltration[END_REF]. The respective impact of these different fouling mechanisms strongly depends on the composition of the fluid to be filtered, on the membrane characteristics, on the hydrodynamic conditions as well as on the physico-chemical interactions between the fluid components and the membrane surface and between these components themselves [START_REF] Vernhet | Contribution to the understanding of fouling build up during microfiltration of wines[END_REF][START_REF] Belfort | The behavior of suspensions and macromolecular solutions in crossflow microfiltration[END_REF].

Theory

Filtrations of low concentrated suspensions (concentration in particles lower than 1% in volume), realized at constant pressure, are shown to follow laws described by simple mathematical equations. In this study, two laws, more particularly suitable for the wine filtration, will be considered [START_REF] Lallier | Filtration frontale avec adjuvants[END_REF][START_REF] Ribereau-Gayon P | Traité d'oenologie Tome 2 : Chimie du vin. Stabilisation et traitements[END_REF]: i) Cake filtration i.e. deposit of particles larger than the membrane pore size onto the membrane surface. The thickness of the cake increases along time and the cake resistance is proportional to the thickness of the cake. A filtration governed by cake filtration law is modelled by the following equation: t/V = kV + 1/q 0 where t is the duration of filtration, V is the volume filtered at t, k is a constant, q 0 is the initial flow. ii) Standard blocking i.e. deposit of particles smaller than the membrane pore size onto the pore inner walls, thus reducing the pore size. The equation, which characterizes this law, is following: t/V = k 1 t + 1/q 0 where t is the duration of filtration, V is the volume filtered at t, k 1 is a constant, q 0 is the initial flow. The slopes k and k 1 characterize the fouling phenomenon: a low value of this constant indicates a good filterability of the wine.

The aim of this work was to study the impact, of some wine components (phenolic compounds and yeast extract), as well as some physico-chemical parameters (pH, calcium content) on fouling of microfiltration membranes. The results obtained must enable the determination of the elements (components or parameters) playing a determining role in the fouling of membranes during wine microfiltration.

MATERIALS AND METHODS

Wine and model solutions

As the crude wine is a complex medium, studies were first carried out using "synthetic wines", to determine more easily the effect of some wine components on fouling. Then, experiments were carried out on a real red wine.

Synthetic wine or model solutions

The effect of some wine components on the microfiltration membrane fouling was studied by using 2 synthetic wines: synthetic white wine (named as S.W.) and synthetic red wine (named as S.R.). S.W. is made of ethanol 12% (v/v); glucose 0.5 g.l -1 ; fructose 0.5 g.l -1 ; tartaric acid 5 g.l -1 , malic acid 4 g.l -1 ; citric acid 0.6 g.l -1 , potassium hydrogeno-phosphate 2 g.l -1 ; magnesium sulphate 0.2 g.l -1 ; ammonium sulphate 0.2 g.l -1 . The synthetic red wine has the same composition as S.W. with addition of 0.25 g.l -1 anthocyanins and 0.5 g.l -1 tannins. The initial pH of the solutions is 2.3 and it is adjusted to 3.7 (closed to the usual pH of wine) with a 5N NaOH solution.

Red wine

The red wine used in the present study was elaborated in 2007 at the cooperative cellar of Rabastens from Duras, Fer de Servadou and Syrah grape varieties. To increase the extraction of polyphenolic compounds (anthocyanins and tannins), the flash-release process was used. This process consists of sending a de-stalked, drained and heated (> 85°C) harvest to a vacuum chamber. The juice will instantly vaporize due to the low pressure and the grape skin and the seeds will be deconstructed [START_REF] Ribereau-Gayon P | Traité d'oenologie Tome 2 : Chimie du vin. Stabilisation et traitements[END_REF][START_REF] Flanzy | OEnologie : fondements scientifiques et technologiques[END_REF]. After alcoholic and malolactic fermentations, the wine was centrifuged at the cellar in order to remove microorganisms and particles (size greater than 0.65 µm). When received, the wine was analyzed and maintained at 4°C until use.

Microfiltration experiments

The experiments were carried out in an Amicon cell manufactured by the Amicon-Millipore company. This cell is a polyethylene cylinder, having an internal diameter of 40.7 mm, containing 60 ml of solution. Its lid is provided with a valve to slacken the pressure. The membrane lays on a fine plastic grid. The maximum pressure of operation is of 5.2 bars. This cell allows a dead-end or pseudo-tangential filtration. All filtration experiments are carried out in the dead-end mode.

Filtrations are carried out on samples of 500 ml of solution. The membranes used are cellulose acetate microfiltration membranes (flat sheet type) with 0.2 µm pore diameter, filtration area of 1.3x10 -3 m 2 . Gaseous pressurized nitrogen ensures the driving force allowing the passage of the liquid through the pores of the membrane (air was not convenient because it can modify the physico-chemical properties of the wine by oxygenation). The pressure was maintained at 2 bars for all experiments. A balance, connected to a computer for the acquisition of the data, makes it possible to measure the effective flowrate by measuring the cumulative liquid mass. Filtrations are carried out at room temperature (22-24°C).

A compaction procedure for the membranes preceded all filtrations to insure reproducibility of the membrane initial state, and thus eliminating "membrane effect". This compaction is carried out by circulating osmotic water through the membrane. This circulation is done in 3 steps. The first consists in circulating the liquid at 3 bars pressure during 10 minutes. Then, the liquid is circulated at 2 bars pressure during 5 minutes and at the third step, the liquid is circulated at 1 bar pressure during 5 minutes.

Analytical methods

Spectrophotometric analyses were carried out on an Agilent 8453 UV/VIS spectrophotometer. The Bradford's method was used to evaluate the proteins concentration by absorbency at 595 nm. Total polyphenols in wine were estimated by the Total Polyphenol Index (TPI) using the absorbency at 280 nm and under 1 cm optical path. Total polysaccharides were determined using the modified Usseglio-Tomasset method based on the precipitation of the polysaccharides with ethanol [START_REF] Usseglio-Tomasset L | Les colloïdes glucidiques solubles des moûts et des vins[END_REF]; this method is also used to determine mannoprotein concentrations. Total anthocyanins were determined according to Ribéreau-Gayon method using the sodium bisulphite [START_REF] Ribereau-Gayon P | Traité d'oenologie Tome 2 : Chimie du vin. Stabilisation et traitements[END_REF]. Total tannins were also determined according to Ribéreau-Gayon method by transforming the proanthocyanidins into antocyanidins [START_REF] Ribereau-Gayon P | Traité d'oenologie Tome 2 : Chimie du vin. Stabilisation et traitements[END_REF]. Colour Intensity (IC) is the sum of optical densities at 420 nm, 520 nm and 620 nm [START_REF] Ribereau-Gayon P | Traité d'oenologie Tome 2 : Chimie du vin. Stabilisation et traitements[END_REF]. Tartaric acid concentration was determined by colorimetric method using ammonium metavanadate. % of alcohol, malic acid, glucose and fructose concentration were determined on the wine by FTIR spectroscopy (Fourier Transform Infra Red spectroscopy). Total and free SO 2 were determined by iodine. Table 1 shows the composition of the wine.

RESULTS AND DISCUSSION

The results of filtrations are represented by graphs of normalized fluxes (J/J 0 ) according to time which allows us to eliminate the J 0 variations between the membranes (J 0 is the flux obtained by filtering osmosed water). The law(s), which suit to each filtration, is (are) determined by a graph t/V = f(t) or t/V = f(V) according to the type of fouling.

Effect of phenolic compounds

Phenolic compounds are responsible of the strong decline of filtration flux for S.R. solution compared to the flux of the S.W. solution. Figure 1 enables us to follow the profiles of normalized fluxes obtained by filtrations of six synthetic red wine solutions containing different concentrations of phenolic compounds (S.W. + 0.25 g/l anthocyanins; S.W. + 0.5 g/l anthocyanins; S.W. + 0.5 g/l tannins; S.W. + 1g/l tannins; S.R. = S.W. + 0.25 g/l anthocyanins + 0.5 g/l tannins; S.W. + 0.5 g/l anthocyanins + 1 g/l tannins). The concentrations used are in the range of actual concentrations found in the oenological practices, as quoted in the literature. The profiles of the curves indicate clearly that the solutions containing the two species of phenolic compounds (anthocyanins and tannins) exhibit a more important flux reduction than those containing only one specie of phenolic compound (anthocyanins or tannins). This can be explained by the fact that anthocyanins and tannins may react together to yield to an anthocyanin-tannin complex with bigger molecular size, this condensation being done via ethanal molecules present in the solution. It is suspected that ethanal is issued from uncontrolled oxidation of ethanol during storage [START_REF] Flanzy | OEnologie : fondements scientifiques et technologiques[END_REF][START_REF] Cheynier | Stabilisation tanins-anthocyanes, données générales[END_REF].

V (ml) t/V (s/m l)

S.W. + 0.5 g/l anthocyanin + 1 g/l tannin S. R. When considering the effect of some species on filtration, it is clearly seen that the flux reduction when doubling the quantity of tannins, while the anthocyanin concentration is maintain, is almost similar than in the case of 2 selected amounts. Indeed, it has been shown that tannins are likely to form metastable colloidal particles at such concentration in the wines. The size of the aggregates depends on the tannin concentration and their degree of polymerization [START_REF] Ribereau-Gayon P | Traité d'oenologie Tome 2 : Chimie du vin. Stabilisation et traitements[END_REF][START_REF] Flanzy | OEnologie : fondements scientifiques et technologiques[END_REF][START_REF] Vernhet | Interactions physico-chimiques : Implications en oenologie, habilitation à diriger des recherches[END_REF]. The molecules of anthocyanins may also form complexes between themselves, although a hydro-alcoholic solution, and wine in particular, is not a favorable medium for this phenomenon [START_REF] Vernhet | Interactions physico-chimiques : Implications en oenologie, habilitation à diriger des recherches[END_REF]. So increasing the anthocyanin concentration did not show a significant effect on the wine filterability Figure 2 and 3 show the standard blocking law and the cake filtration law, respectively applied to filtration of these solutions. Such a representation of the results enables us to understand the behavior of the fouling in each solution. We note that filtration of solutions containing only one species agrees with the standard blocking law, while the cake blocking law seems to better describe the filtration of S.R. containing 0.25 g/l anthocyanins and 0.5 g/l tannins. Solution containing 0.5 g/l anthocyanins and 1 g/l tannins seems to be in agreement with the both laws.

R 2 = 0,9961 R 2 = 0,9972 R 2 = 0,9978 R 2 = 0,9974 R 2 = 0,9827 0 0,2 0,4 0,6 0,8 1 1,2 1,4 1,6 1,
As a conclusion of this part, it is pointed out that, when only one specie is present (either anthocyanin or tannin) a progressive blocking of pores seems to be the limiting phenomenon, while, when the two species are present (as in the case of S.R.) the fouling by cake formation is likely to be occurring, because of complexation between anthocyanin and tannin. Nevertheless, for high concentrations of these both products (as in the case of S.W. + 0.5 g/l anthocyanin + 1g/l tannin), the ethanal concentration is probably not sufficient to insure the complexation of all species. So, remaining free anthocyanin and tannin molecules may participate to a progressive inner blocking of the membrane and because both mechanisms are present in this case, this may explain why none of the both laws are suitable here.

Effect of yeast extract

The yeast extract is an autolysate of yeasts Saccharomyces Cerevisiae where cell-walls have been eliminated. Such an extract is a good source of amino nitrogen and vitamins, especially vitamin B. The yeast extract is added when fermentations are qualified as "difficult", or to accelerate the fermentation. These compounds can be also found naturally in the wine after the ageing process or when any fining agent is used.

Three synthetic solutions (S.R., S.R. + 0.25 g/l yeast extract and S.R. + 0.5 g/l yeast extract) were filtrated. A strong flux decrease is observed when yeast extract is added, and fouling is more important when the quantity of yeast extract is doubled. The composition given by the yeast extract provider (OXOID) mentions only inert compounds, with respect to fouling (amino-acids, vitamins and minerals). Therefore, specific yeast extract analyses were carried out at the laboratory: no mannoproteins (a compound usually found in cell walls and known for its strong effect for membrane fouling) were found. However, analyses revealed the presence of 300 mg/g of equivalent BSA proteins (bovine serum albumin).

Filtration behaviour of these solutions was found to obey perfectly the cake filtration law. Cake formation on the surface of the membrane is probably due to anthocyanins-tannins complexation, but mainly to tannin-proteins complexation and to protein aggregation. Indeed, tannins have the capacity to complex with proteins by hydrogen bonding or hydrophobic interactions, yielding stable complexes [START_REF] Ribereau-Gayon P | Traité d'oenologie Tome 2 : Chimie du vin. Stabilisation et traitements[END_REF][START_REF] Vernhet | Interactions physico-chimiques : Implications en oenologie, habilitation à diriger des recherches[END_REF].

To point out this suspected "protein effect" on solution filterability, proteins were removed by addition of bentonite. Indeed, bentonite is a widely used fining agent in oenology for the stability in respect to protein breakage. At usual pH of wine, bentonite is a negatively charged clay on which positively charged proteins, at the same range of pH, adsorb [START_REF] Ribereau-Gayon P | Traité d'oenologie Tome 2 : Chimie du vin. Stabilisation et traitements[END_REF][START_REF] Flanzy | OEnologie : fondements scientifiques et technologiques[END_REF]. Thus, large neutral particles are formed, which flocculate then settle when their size allows it. 0.4 g of bentonite were been added to 1 L. of S.W. + 0.5g/l yeast extract. After 24 hours, 0.25 g/l of anthocyanin and 0.5 g/l of tannin have been added to the clear liquid phase (C.L.) which is free of proteins. Phenolic compounds, positively charged, have been added after fining because they can adsorb on bentonite [START_REF] Ribereau-Gayon P | Traité d'oenologie Tome 2 : Chimie du vin. Stabilisation et traitements[END_REF][START_REF] Flanzy | OEnologie : fondements scientifiques et technologiques[END_REF]. This solution (C.L + 0.25 g/l anthocyanins + 0.5 g/l tannins) is filtered. In this case, we can observe (figure 4) that the fluxes curves of S.R. and C.L + 0.25 g/l anthocyanins + 0.5 g/l tannins are similar, which illustrates clearly the fouling effect of proteins issued from yeast extract addition. C.L + 0.25 g/l anthocyanins + 0.5 g/l tannins S.R. + 0,5 g/l yeast extract S.R.

Fig. 4. Effect of fining on the filtration

Influence of pH

The charge of colloids in the wine, especially proteins and anthocyanins, depend directly on the pH of wine [START_REF] Flanzy | OEnologie : fondements scientifiques et technologiques[END_REF][START_REF] Vernhet | Interactions physico-chimiques : Implications en oenologie, habilitation à diriger des recherches[END_REF]. Two pH were selected (3.3 and 3.7) to evaluate the influence of pH on filterability of two solutions (S.R. and S.R. + 0.5 g/l of yeast extract).

It is observed that lowest pH (3.3) leads to an improvement of the filterability, for the two solutions (S.R. and S.R. + 0.5 g/l of yeast extract), and that all the filtrations are found to obey the cake filtration law. For the S.R. solution, decreasing the pH to 3.3 induces the modification of anthocyanins into its flavylium form (AH + ), which is evidenced by an increase of the red coloration of the liquid. The presence of AH + ions was checked by measuring the optical density at 520 nm (wavelength at which these ions present the highest absorbance). Flavylium forms are not likely to aggregate because their positive charge is responsible of repulsive forces between molecules [START_REF] Ribereau-Gayon P | Traité d'oenologie Tome 2 : Chimie du vin. Stabilisation et traitements[END_REF][START_REF] Flanzy | OEnologie : fondements scientifiques et technologiques[END_REF][START_REF] Cheynier | Stabilisation tanins-anthocyanes, données générales[END_REF].

For S.R. + 0.5g/l yeast extract, a flux increase is observed when decreasing pH. Indeed, the pH of the solution determines the type and the total charge of proteins, thus modifying the electrostatic interactions. The pH influences dramatically the rate of aggregation of proteins: when the pH values are close to the isoelectric point of proteins (usually close to 4 for proteins present in the wine), the very anisotropic distribution of charges may create dipoles [START_REF] Ferreira R | The wine proteins[END_REF]. In this case the protein-protein interactions can be highly attractive, favoring aggregation, and thus membrane fouling. When decreasing the pH of the solution, the number of the charged groups on the protein surface is increased and repulsive forces are predominant, preventing from protein aggregation [START_REF] Krishnan | Physical stability of proteins in aqueous solution: mechanism and driving forces on nonnative protein aggregation[END_REF]. This phenomenon is accounting for the significant improvement in the case of filtration of SR + 0.5 g/l of yeast extract.

Wine filtration

The evolution of the normalized flux obtained during filtration of the red wine presents a very important flux decline, much more important than observed for synthetic solutions. This decline is particularly important in the first minutes of filtration and flux tends rapidly towards zero while progressing in filtration, indicating total fouling of the membrane by specific wine components. By analyzing the wine, the results presented in table 1 revealed very high concentrations of colloidal compounds, compared to those usually present in the literature. We suspect that it is due to one step ("flash-release") of the specific wine making process of the wine we have used in this study. We can also note the low total polysaccharides content which is due to the use of the pectolytic enzymes (degrading the pectic substances). Indeed, this type of wine was not well adapted for the procedure (dead-end filtration) of our study, and choice of a more suitable wine is under progress.

CONCLUSION

The present work was conducted with the aim to determine the effect of wine components and of some physico-chemical parameters on the fouling of microfiltration membrane. We tried also to define the type of fouling which governs each filtration. It was demonstrated that the simultaneous presence of the 2 species of phenolic compounds has a synergistic detrimental incidence on the membrane fouling, than the presence of one single species. Adding yeast extract, a widely used agent in oenology, lead to increased fouling, due to the presence of proteins in the yeast extract. The pH has also an incidence on solution filterability: improvement in flux filtration was found in the case of low pH.

Additional analyses, like particle size distribution, zeta potential… are still needed to monitor the particle distribution evolution, their charge, and the formation of aggregates along the time. These analyses will provide better understanding of the specific fouling phenomena related to wine processing.

Fig. 1 .

 1 Fig. 1. Incidence of phenolic compounds on normalized fluxes

Fig. 2 . 3 .

 23 Fig. 2. Standard blocking law Fig. 3. Cake filtration law

Table 1 .

 1 Concentration of wine components and comparison with colloids concentrations quoted in the literature. * Components expressed in g/l H 2 SO 4

		TAV	pH	Total ac.*	Tartaric ac.*	Malic ac.*	Volatile ac. *	Total SO 2	Free SO 2
	Wine	11.9	3.65	4.18 g/l	4.2 g/l	0.1 g/l	0.33 g/l	37 mg/l	30 mg/l
		Proteins	Total Polysacch.	Total tannins	Total Anthocyanins	IPT	IC
	Wine	621 mg/l	360 mg/l	3.42 g/l	984.4 mg/l	72.7	13.52
	Literature	15-230 mg/l	2 -4 g/l	1 -4 g/l	100 -500 mg/l


Bénédicte Bucher
email: benedicte.bucher@ign.fr

Marcin Grudzień
email: marcin.grudzien@gugik.gov.pl

Nathalie Delattre

Jordi Escriu Paradell

Erwin Folmer

Antonin Garrone

Antje Kügeler

Ángel Lopez

Ed Parsons

Andrea Perego

Jiri Pilar

Jari Reini

Hannes I Reuter

Jill Saligoe-Simmel

Maja Schneider

Jeroen Ticheler

GEODATA DISCOVERABILITY Joint Workshop of EuroGeographics and EuroSDR April 28 th 2022 -Online With 23 figures and 1 table

Example of display of a data source on data.europa.eu: description and preview ......... Figure 9:

Overall architecture and technologies considered in the data store infrastructure ......... Table 1: Harmonised Geodata discoverability was identified decades ago as a crucial challenge both by the Spatial Data Infrastructure (SDI) community and, for the more general case of data discoverability, by the Web of data community. It has kept growing in the late years.

Index of Tables

SDIs adopt distributed infrastructures to lower the cost of data acquisition by reusing available data instead of producing new ones [START_REF] Masser | All shapes and sizes: The first generation of national spatial data infrastructures[END_REF]. A core function on distributed infrastructures is the discovery of available data, initially addressed through catalogue services. Another motivation for SDIs is to ensure trust by using data from the relevant authorities like, for example, reusing member state data to establish and monitor European policies. This also implies that member state data that are relevant to a European decision can be discovered ahead of this decision. The INSPIRE SDI was established by the European Commission for supporting the sharing and reuse of member state data produced by legally mandated authorities and relevant to European environmental policies (EP 2020).

The Web of data is more focused on increasing the value of data by allowing new usages beyond their initial purpose. Hence, data should be visible from developers with diverse backgrounds and levels of expertise in the domain of these data [START_REF] Berners-Lee | The Semantic Web[END_REF].

This stake of data discoverability has kept growing lately for many reasons. Second reason is the rising awareness that data is an opportunity to better cope with the complexity of our world during decision-making. For example, at the international level, a set of sustainable development indicators has been proposed by the United Nations to cover all possible aspects of UN Agenda 2030 like, for example, access to water, to food, to education, prevent war, no poverty, and inclusive cities. The main motivation for these indicators is to monitor quantitatively how our planet evolves. Another purpose that they also serve is to gather yearly data to understand the interdependencies between these different dimensions of sustainability. All in all, in order to describe our world complexity that is relevant to a decision at stake, one may need data with different thematic focuses and different levels of detail, possibly also different spatial and temporal scopes. These data usually refer to different platforms, providers, technologies, and communities, which makes their discovery complex from the user perspective. Everyone is welcome to publish on the portal both datasets and reuse. Moderation is done postpublication by Etalab.

In that context, the multiplicity of models and issues in fields correspondences of these models (DCAT, ODS, CKAN, UDATA, etc.) can jeopardise data discoverability, as well as possible low quality of metadata.

A key topic is thus the data models interoperability. Schema.data.gouv.fr has been designed to create and reference data schemas in order to enhance discoverability, reusability and interoperability of data on data.gouv.fr. This key aspect is illustrated on figure 4. It is associated with publier.etalab.studio, a tool to edit, validate and publish data structured according to a schema. Examples of schemas are : the National Address Database and the Infrastructure for electric vehicle recharge.

Figure 4: Snapshot from schema.data.gouv.fr, a portal to support the creation, publication or reuse of data models.

Last, to enhance data discoverability, etalab prepares and curates specific outputs to present directly to users 'essential' geographical datasets.

Discoverability of open agriculture data

Maja Schneider, Technical University of Munich

Within the EuroCrops project, open agricultural data from member states of the European Union has been collected over the past one and a half years. Most notably, farmers' self-declarations, including the georeferenced polygon with the crop information gathered for the subsidy control, have been the primary focus for the project. In last years, an increasing number of ministries and paying agencies have decided to make this data publicly available.

However, the theoretical availability of the data does not necessarily make it straightforwardly accessible because of heterogeneities of data release practices, as illustrated in figure 5. While platforms such as the INSPIRE Geoportal or data.europe.eu exist and offer the appropriate access tools, the majority of the data can only be obtained by digging through often untranslatable national websites or contacting the appropriate responsible staff directly via email. From a total of 16 countries (Austria, Belgium, Germany, Denmark, Estonia, Spain, France, Croatia, Lithuania, Latvia, Netherlands, Portugal, Romania, Sweden, Slovenia, Slovakia) that have released the data, only one used INSPIRE Geoportal, two published on data.europe.eu, three gave out the data via eMail, and the remaining states had the data only available on their respective websites. Some countries, including Spain, Belgium, and Germany, do not release the data on a national level; to get access to the information, one must visit an additional website for each region. Finally, when all available data is collected, the next interoperability problem arises: Published crop data does not follow a European standard and is therefore not comparable in any way. As a consequent step, harmonising the data is required. In the EuroCrops dataset, we introduced a new Hierarchical Crop and Agriculture Taxonomy (HCAT), which maps all country-dependent taxonomies into one unified schema, see table 1. Due to its hierarchical structure, any granularity in which the crop data might be declared, can be reflected and stored. In 2022, the Commission identifies a list of 'high-value datasets', whose re-use can bring benefits for society, the environment, and the economy, see figure 7. Such data will have to be available for re-use for free, in machine-readable format, via APIs and, where relevant, as a bulk download. Geospatial data will represent a very important part of high-value datasets. In addition, two other upcoming pieces of legislation partly concerns public sector data: the Data Governance Act and the Data Act. To facilitate public data sharing it is possible to search across countries and particular thematic domains.

The titles and descriptions of the described datasets are translated into the different European languages after the harvesting to allow a multilingual search. The users can discover data from different countries even if they do not speak the languages the data is described in.

Some popular geospatial content (Web Map Services -WMSand GeoJSON) can be previewed in the map viewer that is part of data.europa.eu, see figure 8.

Apart from the different options to search for, browse and discover data on data.europa.eu, it is important to keep in mind that some users may not even be aware of the portal's existence and its content. These users will be more likely to use mainstream search engines than go to specialised data portals. To enable discoverability outside of data.europa.eu special information (schema.org in JSON-LD encoding) is included in the html pages. This is not visible to human users but makes it easier for search engines to index the content, allowing datasets to be found with mainstream search engines.

7

The Copernicus Data Stores implemented by ECMWF

Ángel Lopez, Copernicus

Copernicus is the European Union earth observation program and combines different kinds of satellites.

The European Centre for Medium-Range Weather Forecasts (ECMWF) has been mandated to implement and run specific Copernicus services based on these satellites data : Climate Data Stores (CDS) and Atmosphere maintained by a DevOps team. The design is flexible and adapts to different technologies currently adopted by users to search datasets, as well as an APIto access the datasets, https://cds.climate.copernicus.eu/api-how-to, see figure 9. The vision developed after this analysis considers:

• the evolution of INSPIRE to the concept of data ecosystem.

• broadening its scope to new sectors (not only the public sector, but also the private sector/businesses, and academia). • engaging with new communities, such as developers, and end users.

• widening the range of applications and use cases.

• making the INSPIRE framework simpler, more flexible and agile.

• lowering the knowledge entry-level for implementing and/or using data.

• reusing well-adopted standards and technologies that proved to be in use.

The INSPIRE Geoportal (https://inspire-geoportal.ec.europa.eu), which is the main access point to INSPIRE Infrastructure tools and resources, is now being revamped, including a new user interface (frontend) which will include the possibility to browse and filter INSPIRE datasets according to High-Value Datasets categories envisaged in the Open Data Directive, as well as a new catalogue system (backend) based on GeoNetwork open source, using an architecture migrated to a cloud environment.

Moreover, the JRC is researching to establish the technical and non-technical requirements for the evolution to European data spaces. The outcomes are being included in a 'Data Spaces Cookbook', cocreated and validated with different European Commission services, but also other sub-products have been produced (an online living document, an interactive component / chatbot for Q&A purposes) and are already available. 9

GeoNetwork opensource -New developments and plans

Jeroen Ticheler, GeoCat

GeoNetwork is an open source and standards-based technology to manage and expose spatially referenced resources. The tool started in 2000 at the Food and Agriculture Organisation of the United Nations (FAO) only counting with one developer. Now it is supported and used by an active and global community of developers and users. There are around 1000 software downloads per month and its technology is used by 85% of the current national INSPIRE catalogues (discovery end-points). Metadata edition and multilingual metadata support was the focus of version 3 of the software.

The latest version of the tool, v4, focuses on the searching functionality. Its architecture is displayed in figure 12. It integrates spatial search within the index, and is about 10 times faster than the old searching mechanisms. Both, index and search components, run separately from the rest of the application, which improves performance and scalability. With regards to standards, OGC API -Records is an alternative to OGC Catalogue Service for the Web (CSW), and it is implemented on top of GeoNetwork v4. This will still require some refactoring in the future, since the standard is not approved yet and might evolve.

Additionally, GeoNetwork v4 adopts a micro-services architecture as shown in figure 13. This brings benefits, for example the ability to run parallel background tasks, improved resource management, the possibility to mix and match components, scalability and happy DevOps. It required and still requires a modification of the monolithic application GeoNetwork used to be.

Figure 13: Microservices in GeoNetwork v4, © Ticheler, GeoCat New developments have been made for the implementation of the revamped INSPIRE Geoportal. This 'Super Harvester' is based on three new components: 1) an improved and high-performance harvester, 2) a link checker validating the real accessibility of data and services , and 3) an ingestion engine to publish the results obtained from the harvesting processes, see figure 14. GeoDCAT-AP, https://semiceu.github.io/GeoDCAT-AP/releases/, is a geospatial extension to DCAT-AP developed in 2015 by a working group involving experts and stakeholders from EU Member States, chartered by the EU ISA Programme (now Interoperable Europe). The purpose is to increase the discoverability of geodata outside the GI community by adopting a more generic standard and extending this standard to adapt to the specificities of the GI domain, as shown in figure 15. A demonstrator (http://geodcat-ap.semic.eu/api/) was developed to :

• provide a working example on how GeoDCAT-AP can be supported without changing the underlying infrastructure • show how to enable standard HTTP functionalities in CSWs, as HTTP content negotiation • show how to increase visibility on the Web for geospatial metadata, using standards as HTML+RDFa

Lessons learned after GeoDCAT-AP v1 (2015) were identified. There is a lack of common practices to specify some geospatial information in RDF. The use of global & persistent identifiers in geospatial metadata is too limited. Version 2 of GeoDCAT-AP was released in 2020 and addresses these limits together with the latest versions of the INSPIRE Technical Guidelines for identifiers.

11

OGC API featuresbuilding blocks to create, modify, and query geospatial vector data on the Web Jari Reini, National Land Survey Finland API development at National Land Survey in Finland is driven by several considerations. NLS Finland's data is extensive and constantly updated. Timeliness is a key factor for the user. The users need the data as part of their own process and information systems. Last, with the issue of the EU's Open Data Directive, NLS data are among HVD's (High Value Datasets).

In that context, the Spatial Data on the Web Best Practices are :

• to use globally unique persistent HTTP URIs for Spatial Things • to make your spatial data indexable by search engines

• to use spatial data encodings that match your target audience • to expose spatial data through 'convenience APIs'

• to include spatial metadata in dataset metadata Additional recommendations are listed as being FAIR: Findable (through catalogues and metadata), Accessible (by using an open and standardised protocol), Interoperable (using standards for content encoding) and Reusable (by providing licence information and data product specifications).

In that context, the OGC APIs are new standards that take advantage of modern web development practices to define resource-centric APIs: Features, Maps, Records, Processes, Coverage, Environment Data Retrieval. They build upon the legacy of the OGC Web Service standards (WFS, WMS, WCS, WPS, etc.) and are being constructed as "building blocks" to support download, updating, processing, view and discovery.

Figure 16: Implementation of OGC APIs on NLS portal, www.nls.fi NLS has adopted OGC APIs for its open data to be published online : background maps, spatial data (such as place names, roads, buildings, addresses, water bodies and other terrain patterns, elevation ratios and administrative boundaries), real estate information, residential and commercial property information. The portal is shown in figure 16.

12 Linking Authoritative (Government) data with Community data (e.g. Wikidata)

Erwin Folmer, University Twente Data about buildings is stored in different kinds of datasets; including government data, commercial data, and community data. Most of these datasets have been set up as silos. There is a lot of potential in connecting all those isolated data containers. It makes more value for the end user, by t improving the quality by redundancy and complementarity of the sources. In that context, a lot of effort has been put on connecting data from different origins within government sources into a Knowledge Graph, illustrated in figure 17.

Figure 17: Interconnection of government data related to a building with the Kadaster Knowledge Graph, © Folmer, Uni Twente

Next step is to connect with other data, to reach the potential of linking to community data.

Kadaster investigated the creation of links between Wikidata and the Dutch Cadaster, as shown in figure 18. While Kadaster created 50 links in 2020, over 20 000 links have been created by the community, to associate buildings with community data like, for example, images. As the creation and maintenance of data like the Base Registry for Topography (BRT) is expensive, a relevant question is the enrichment of buildings data with an external open data source (e.g. OpenStreetMap). The project explored which building types and OSM data will contribute to the highest value creation. It automated the OSM data ingress process, created a geometric match and transformed OSM to Linked Data (including geometric links) and connects to the existing BRT Linked Data set, as illustrated in figure 19.

Figure 19: Linking Base registry for Topography (BRT) with Wikidata and OSM, © Folmer, Uni Twente This process is not straightforward and the project found many semantics and quality issues. Several challenges need to be solved to achieve quicker and effective output. So to say, there is a big win but not a quick win.

13

Beyond SDI? Becoming cloud native?

Ed Parsons, Google

Cloud technology calls for an upgrade of SDI infrastructure to reach cloud native SDIs. Access and usability are the two pillars of successful spatial data publishing. Metadata harvesting is not enough. Data must be discoverable by automated systems and data must itself be directly accessible and linkable on the Internet. Big volumes of spatial data, especially earth observation (EA) data, requires streamable data formats.

A starting point for dataset search from Google perspective is to follow 4 steps illustrated figure 20: add markup to the dataset pages, verify the markup, and submit a site map.

Another approach is to enhance data discovery by browsing.

Last, data must be steamable to manage large volumes. How we think of traditional Spatial Data Infrastructure (SDI) is evolving. Because, of course, technology is not static but is constantly evolving. Geospatial data supply chains are shifting from a hierarchical to circular data economy, with digital communities of practice consisting of data providers, coordinating bodies, and data consumers. Today, organisations come together to collaborate and share in digital ecosystems, a truly integrated geospatial infrastructure, as illustrated in figure 21. New patterns for modern SDI are shifting paradigms from search and discovery to integration and use. How do we maximise geodata discoverability and access in this system of systems? Activities that promote discoverability and access must span the end-to-end workflow of providers who produce, publish, collaborate, share, and (re)use data, see figure 22. For example, data providers at all levels of government and across all industries produce and manage data and metadata using domainrelevant community and international standards. These organisations then publish data as interoperable web services and APIs using open standards and specifications, ensure their content has proper metadata, and carry appropriate licensing. Digital ecosystems place a renewed emphasis on data consumers. Data producers realise increased return on investment as shared web services are used and reused. In addition to web services, sharing through maps and apps, where data are visualised and explored, expands data access to broad audiences who may be unfamiliar with GIS. As a result, value is unlocked as data are accessed and used to drive decision-making and innovation.

Today, this vision is materialising among thousands of organisations worldwide. Tools are helping to maximise discoverability and access through user interfaces, automation, workflows, infrastructure, interoperability, and compliance in ways that are easy to implement. As a result, an interconnected system of systems is quickly emerginga global digital ecosystemenabled by geospatial infrastructure that empowers organisations to collaborate and be more effective than ever. The OGC is finalising the new OGC -API Records standard, which will highly simplify the discovery, access and management of metadata on the web. In addition, the SpatioTemporal Asset Catalogues (STAC) has been identified as an emergent de-facto standard for publishing geospatial data catalogues online. Finally, GeoDCAT-AP is being highly used for making spatial data publicly and consistently accessible in both, the Open Data and the geospatial domains. As illustration, OGC API -Records has been already endorsed as a INSPIRE Good Practice candidate to simplify not only the discovery, access and management of metadata on the web, but also to make such resources automatically discoverable through search engines.

As final reflections on data discovery, future metadata models should be storing the information in a standard-agnostic way, and metadata catalogue tools be based on the emerging standards mentioned hereabove. Besides, users expect simple, understandable communication in user interfaces (frontends), such as searching based on Natural Language Processing (NLP), data filtering, and levelled exploration of results. Metadata results should be automatically translated to the user's language and adapted to the user's knowledge. Finally, the frontend shall not be necessarily coupled to the SDI geoportal / catalogue.

16

Wrap up poll

The last session was dedicated to a live poll between participants who were willing to participate. The first question was answered by 21 participants. The latter were answered by an average of 12 participants.

Question: What are you looking forward to from this workshop? (free text answers)

Question: As a data provider, when publishing information about spatial dataset on the Internet, please prioritise tools you use to improve the dataset discoverability. Put the most used tool at the top, and the least used at the bottom.

Question: As a data user, when searching for information about spatial dataset on the Internet, please prioritise the tools you use to find relevant data. Put the most used tool at the top, and the least used at the bottom.

Question: Do you use other tools than those mentioned in the previous question to find spatial data? 7 answers No.

Other: local authority data portal, national geoportal, kohesio, zenodo, local contacts Question: What insights do you require from discoverability tool providers regarding their tools? (free text answers)

• Completeness of coverage

• Easy-to-use editor, with automatic aids. Ability to transform metadata on-the-fly and serve the information in a wide range of standards. Bridging the gap across different domains (eg Geospatial vs Open data). Metadata exposed through the use of geospatial discovery APIs. Automatically discoverable through Web search engines. Discovery service (backend) in the cloud.

• Support of standards from the 19100 series as well as OGC. In addition to this we all look on how to integrate with our production system

• How to ensure that the published data is discoverable by a search engine, is compatible with a national portal, and that published metadata can be easily updated.

• Transparency, metadata

• Detailed manuals and tutorials

• How they rank (Google dataset search).

Question: Do you think that data providers are doing enough to improve their data discoverability?

Question: What makes spatial data discoverability so different from other data discoverability (please provide keyword)?

Question: What would you demand of spatial data discoverability in order to generate a business value?

(free text answers)

• Easiness of discoverability • Being integrated in Web search engines. Simple, understandable communication with the user. Including NLP search, data filtering capabilities, levelled exploration of results. Automatic translation of metadata Discovery application not necessarily coupled to the SDI geoportal / catalogue. • data which are usable not requiring XX days to get it working • I don't know about business value but lots of missed data use and opportunities due to lack of discoverability • End users must be taken into account -not only the developers but also the citizens/decision makers. They also need to know something about the quality of the data used e.g. for the COVID dashboard to see if they should trust the information (and hence need some basic data literacy to understand enough to know whether to trust what they see). • open data • For the data providers, a key factor is finding new users for the data. Therefore, I am investigating if discoverability returns a specific number of new users. For data users, a key aspect is the efficiency of search tools. Meaning how fast I find the data I need.

Question: Do you have any suggestions for follow-up activities?

• Hands-on workshop • Have another workshop where we could have some more open discussion and interaction between the speakers and audience. • Report will be of great interest. A session during next INSPIRE conference Provide feed-back to MIG-T. Difficulties of users in searching data to be widely communicated (e.g. by INSPIRE community) => encourage efforts from data providers, search engine • Thanks everyone for a great workshop! For follow up as well as publishing all the videos and the slides and polls etc, could we maybe organise something similar with more of a developer perspective -i.e. to find out what do developers / analysts/ AI machine learning people who are using the data need to know? How do they feel about discovering data? Can they find what they need? Also publish a list of where funding is available for research into this topic. • Hands on and practical sessions: Some tutorials about how to implement some of the things we've seen ... how do you build linked-data/rdf? How to query linked-data? Knowledge Graph? How to produce linked data? How to build a taxonomy etc. How to use various tools (from catalogue to cloud tools) • Organise a follow-up event, inviting geospatial data providers, specifically asking them which geodata discoverability aspects would change after having attended this workshop. In particular, different users must be considered, developers -of different components-and end users who make decisions or produce derived knowledge based on the data. Discoverability of data should not be a preliminary sequence in the development of applications but rather be intertwined with the development and exploitation of the data.

There are many technical solutions, possibly emerging, to improve the current situation, and neither existing solution is universal for every use case. In most cases, optimising geodata discoverability requires utilisation of different tools and technologies which complement each other. Tools combination maximises the chance of potential users to find data relevant to their needs.

Last but not least, the workshop evidenced the relevance of knowledge exchange on that topic and the willingness of participants to renew the experience, to get data providers more involved on this topic, to tackle more technical aspects and organise tutorials and hands-on sessions. After this broad scope, participants suggested to structure follow-up exchanges through community focuses.

  Figure 1: Global Statistical Geospatial Framework .........................................................................

Figure 2 :

 2 Figure 2: Workflows for establishing pan European datasets .......................................................

Figure 3 :

 3 Figure 3: Products that compose Open Maps for Europe .............................................................. Figure 4: Snapshot from schema.data.gouv.fr, a portal to support the creation, publication or reuse of data models. ...............................................................................

Figure 5 :

 5 Figure 5: Heterogeneities of data release within Europe ...............................................................

Figure 6 :

 6 Figure 6: European strategy for Data .............................................................................................

Figure 7 :

 7 Figure 7: High Value Datasets and Common European data spaces .............................................

  Figure 8:Example of display of a data source on data.europa.eu: description and preview ......... Figure9:Overall architecture and technologies considered in the data store infrastructure .........

Figure 10 :

 10 Figure 10: Additional resources provided by the CDS to process data ...........................................

Figure 11 :

 11 Figure 11: Sectoral European data spaces .......................................................................................

Figure 12 :

 12 Figure 12: GeoNetwork v4 architecture .......................................................................................... Figure 13: Microservices in GeoNetwork v4 ..................................................................................

Figure 14 :

 14 Figure 14: Example of results from the link checker component. ...................................................

Figure 15 :

 15 Figure 15: Improving the visibility of Geodata on the Web ............................................................

Figure 16 :

 16 Figure 16: Implementation of OGC APIs on NLS portal, www.nls.fi ............................................ Figure 17: Interconnection of government data related to a building with the Kadaster Knowledge Graph ...........................................................................................

Figure 18 :

 18 Figure 18: The same building depicted in the Base Registry and in Wikidata ................................

Figure 19 :

 19 Figure 19: Linking Base registry for Topography (BRT) with Wikidata and OSM ........................

Figure 20 :

 20 Figure 20: Preparing dataset to be searchable by engines ...............................................................

Figure 21 :

 21 Figure 21: Integrated geospatial infrastructure ................................................................................

Figure 22 :

 22 Figure 22: Support for discovery and access spans end-to-end workflows .....................................

Figure 23 :

 23 Figure 23: Collaboration in cloud-native platforms ........................................................................

  Lithuanian data, 2021 .................................................................................... 1 Introduction

First

  reason is the growing amount of available data. With the development of sensors, of social networks and the digitisation of processes, our societies produce more and more data. Let us mention some examples, such as data acquired by satellites, or data produced by collaborative online communities. Data is also more published, following the development of open data policies to improve the transparency of administration and, more generally, as a paradigm to support trust and innovation. In Europe in particular, the amended version of the Public Sector Information Directive is entitled Open Data Directive (Directive (EU) 2019/1024).

Figure 5 :

 5 Figure 5: Heterogeneities of data release within Europe, © Schneider, Tech Univ Munich

Figure 6 :

 6 Figure 6: European strategy for Data. © European Commission

Figure 7 :

 7 Figure 7: High Value Datasets and Common European data spaces. © European Commission.

Figure 8 :

 8 Figure 8: Example of display of a data source on data.europa.eu: description and preview.© Kügeler, Con Terra

Figure 9 :

 9 Figure 9: Overall architecture and technologies considered in the data store infrastructure, © Copernicus

Figure 11 :

 11 Figure 11: Sectoral European data spaces, © European Commission.

Figure 12 :

 12 Figure 12: GeoNetwork v4 architecture, © Ticheler, GeoCat

Figure 14 :

 14 Figure 14: Example of results from the link checker component, © Ticheler, GeoCat.

Figure 15 :

 15 Figure 15: Improving the visibility of Geodata on the Web, © Perego, European Parliament.

Figure 18 :

 18 Figure 18: The same building depicted in the Base Registry (left) and in Wikidata (right), © Folmer, Uni Twente

Figure 20 :

 20 Figure 20: Preparing dataset to be searchable by engines, © Parson, Google.

Figure 21 :

 21 Figure 21: Integrated geospatial infrastructure, © Saligoe-Simmel, ESRI

Figure 22 :

 22 Figure 22: Support for discovery and access spans end-to-end workflows, © Saligoe-Simmel, ESRI

Figure 23 :

 23 Figure 23: Collaboration in cloud-native platforms, © Saligoe-Simmel, ESRI

  With these considerations above, it is no surprise that actors beyond SDI and Web of data specialists, from the public or private sector, with different backgrounds and ambitions at local or global level, face dataset discovery tasks or engage in the design of discovery solutions.In April 2022, EuroSDR and EuroGeographics jointly organised a workshop to share practical experiences, findings and roadmaps related to the discoverability and accessibility of data with a geographical characteristic, including data covered by the INSPIRE directive. EuroSDR is a not-forprofit organisation, established in 1953, linking National Mapping and Cadastral Agencies with Research Institutes, Universities and Companies in Europe to mutualise innovation efforts in spatial data provision, management and delivery. Eurogeographics is an association that gathers National Mapping and Cadastral Agencies, to share and resolve common problems, to manage pan-European projects suchIn the Directorate of Eurostat, a permanent service (GISCO) of the European Commission is installed that answers the needs of Eurostat and the European Commission for geographical information at the level of the European Union (EU), its Member States and regions. To bring Europe closer to citizens and regions, Eurostat continues to make use of georeferenced data by systematically integrating and mainstreaming geospatial information into statistical production and collecting more geospatial data, with a special focus on the core geospatial datasets, for detailed regional and local level statistics. Therefore, one part of GISCO's activities is the creation of pan-European datasets based on authoritative data providers to support activities outlined in the Global Statistical Geospatial Framework, illustrated figure1.Figure1: Global Statistical Geospatial Framework, © UN-GGIM Datasets are identified in various computer systems (e.g. data.europa.eu). Unfortunately, in some countries and for some themes, the GISCO team fails to discover any data through these global catalogues, portals and retrieval solutions. Human intelligence (e.g. via local contacts, social media) is used to complete the information for a given data theme and country. These datasets are then analysed, ingested, transformed, quality assessed and quality controlled. Possible feedback rounds with data provider organisations are initiated with the final aim of a pan-European dataset, see figure2. Services are built on top to support policy analysts in the European Commission or wider public organisations. Figure 2: Workflows for establishing pan European datasets, ® Reuter, Eurostat GISCO has observed some of the following issues while creating pan-European dataset: a) data exists but are not documented in metadata systems (neither European or Member States) or directly hidden, b) several datasets with various specifications exits for the same theme, however are maintained by different organisations, c) dispersed datasets per country without a central authority exists, d) depending on organisations administrative hurdles or a lock down mentality without user centric views are shown, e) officially data are declared to not exists, but commercial datasets exists for the same area, and f) outdated (temporally) and semantically reduced data (e.g. content) are provided officially while rich and timely data exists. Products that compose Open Maps for Europe, © Delattre, NGI Regarding lessons learnt during the project OME, dealing with different metadata encoding and format(INSPIRE and OPEN data) might provide some burden because this duplicates the effort for the provision of the same information. A strategy needs to be established for efficient workflows of metadata harvesting between the different portals to lower the workload.

		Figure 3:
	Eurostat is on a good way in creating pan-European datasets for policy purposes and operational results
	are promising for a series of themes. The progress is hampered by specific countries due to a) non-
	documented and available datasets, b) stability of services, c) performance of services or d) use
	restrictions due to financial demands/legal provision and e) quality of geospatial data provided.
	3	Discoverability of Open Maps for Europe data
		Nathalie Delattre, IGN-Belgium
	Open Maps for Europe (OME), https://www.mapsforeurope.org/, is a project co-funded by the European
	Commission, to deliver free to use maps from more than 40 European countries, as illustrated in figure
	3.
	The purpose is to provide easy access to free-to-use harmonised maps for Europe and realise the benefits
	of the Open Public Sector Information directive. Eurogeographics has developed expertise in producing
	pan-European datasets using official maps, geospatial data and land information from authoritative
	national sources. An important achievement of the project is to confer an open licence to these pan-
	European datasets, to make the maps discoverable, viewable and downloadable through an enhanced
	gateway.

as web-based metadata services and integrated geographic databases, and to become the unified "voice of European National Mapping, Cadastral and Land Registry Authorities". This publication reports the main findings from this workshop. 2 Creation of pan-European geospatial datasets -Experiences in real-life Hannes Reuter, Eurostat This strategy should favour consistent metadata encoding among the portals (INSPIRE and open data, national and European). One solution is that metadata for geospatial information follows INSPIRE standards and that open data platforms adopt these or be able to harvest them without information loss. Valuable conversion tools should therefore be implemented. 4 The experience of the French open data portal Antonin Garrone, Etalab France Etalab is a French administration created in 2011 to foster the development of data based public action. Its main actions are organised around three axes : 1) opening data (data.gouv.fr, api.gouv.fr), 2) exploiting data through data science and artificial intelligence 3) opening public action through "public interest entrepreneurs". "Public interest entrepreneurs" are short term missions taken by civil servants and by salaries from the private sectors. Data.gouv.fr is the single point of entry for national open data in France, accessing the data themselves or referencing portals from specific providers. It has no specialisation in geographical data unlike other eco-systems but rather in open data published by the public sector. With respect to geographical data, a former specific platform was dedicated to geographical open data, geo.data.gouv.fr, which harvested more than 66 catalogues. It is currently finished and shall merge within the INSPIRE French Geocatalogue operated by BRGM.

Table 1 :

 1

Harmonised Lithuanian data, 2021. © EuroCrops By now, for each of the 16 countries, the project has released one year of harmonised agricultural data with the outlook of temporarily extending it within the next year. The dataset, along with additional information, is available on https://github.com/maja601/EuroCrops.

6

Geospatial Data on data.europa.eu

Antje Kügeler, Con Terra Jiri Pilar, European Commission

The European Commission is following the European Data Strategy outlined in 2020, see figure

6

. For open data, it means monitoring and enforcing the transposition of the Open Data Directive in all EU Member States.

  This is done by collecting the metadata of public data made available across Europe in a process called "harvesting". Metadata is harvested both from open data portals and geodata portals and is made available on data.europa.eu. Currently data.europa.eu provides access to descriptions of more than 1 million datasets from 173 catalogues and 36 countries. With respect to geodata, many of the geoportals harvested by data.europa.eu are INSPIRE geocatalogues (or "INSPIRE discovery services"), which are also harvested by the European INSPIRE geoportal. There are also geoportals being harvested by Data.europa.eu that include no INSPIRE metadata or geoportals that include both INSPIRE metadata and metadata on resources not relevant for INSPIRE. During the geo-harvesting process data.europa.eu maps the INSPIRE metadata to GeoDCAT-AP. Not all mapped INSPIRE metadata elements are visible in the front end, to avoid overwhelming users with information, but they all are accessible via the SPARQL endpoint which stores the full result of the INSPIRE to DCAT-AP transformation.

  Rediscovering Spatial Data Discoverability

	Jordi Escriu, Joint Research Center
	During the last INSPIRE Conference 2021, a session on Spatial Data Discoverability trends was offered
	to the community. Metadata catalogues are evolving at a very fast and dynamic pace. Member States
	are developing cataloguing solutions that encompass both INSPIRE/geospatial as well as Open Data
	domains.
	The new developments are pushing the evolution of software components, in particular open source
	ones, making metadata available in multiple national and European infrastructures through different
	standards and rules.

  All these practices have been recently identified by the INSPIRE community in the fields of Spatial Data Discoverability. As a result, they have been proposed as 'INSPIRE Good Practices', which is the mechanism to analyse new trends and working standards available in the market with the view to

	facilitate	its	adoption	in	INSPIRE,	as	part	of	its	evolution	process
	(https://inspire.ec.europa.eu/portfolio/good-practice-library).

  • Geospatial Open Data -EUROGI good practices workshop in May • Design case studies to benchmark solutions 17 Conclusion To conclude this report, much work has been done and is on-going on the topic of (geo)data discoverability. Contributions stem from different actors: software developers, the INSPIRE community, local, national or European open data portals. Discoverability can also be improved by modifying the data themselves and using shared schemas and taxonomies to structure them. Yet, despite these active contributions, progress is still needed. This progress will require the collaboration of different parties involved in the data life cycle and at least a common vision on what discoverability is. It is important to analyse what is discoverability nowadays in the information systems.

Acknowledgement

The authors warmly thank Matina Fuentes, Patricia Sokacova, Alina Talipova and Carol Agius from Eurogeographics for their contribution to the workshop organisation and animation. We also thank Eric Bayers from NGI Belgium, Julián Hernández Delgado from IGN Spain and Joep Crompvoet from KU Leuven for their thorough and constructive reviews of this report.

Data Store (ADS), https://cds.climate.copernicus.eu/, https://ads.atmosphere.copernicus.eu/. CDS and ADS share the same infrastructure operated and

Question: What is the favourite standard used to profile the metadata in your organisation?

Question: What are the key elements you find the most relevant in the metadata discovery content or you would like to get, e.g. links to services, indication whether data is open, lineage, contact to data provider?

Question: What about the conversion between INSPIRE/(Geo)Dcat? Have you implemented specific tools for that purpose?


domain: info sde shs

text:
Bucher B., Cantat F., Crompvoets J., Lisec A., Potůčková M., Cahalane C.,
A panorama of approaches developed by EuroSDR members

In 2019 and 2020, the EuroSDR organization launched a survey to study existing EuroSDR members' initiatives to provide data and tools to second level pupils and their teachers, third level students and their lecturers and scientists. One motivation was to obtain feedback on geodata value and reusability from communities heavily involved in knowledge production and transfer, as well as on methods to improve spatial data literacy. Another motivation was to investigate emerging needs with these communities that may lead to the design of new products.

The panorama presented here is not exhaustive but provides a good representation of what can be found in this area in Europe. Thirty-two initiatives were examined, 10 by mapping agencies and 4 from other organizations. Target groups for these initiatives cover a wide range of participants, from pupils from the age of 5-years to university students and professionals as well as the general public.

Teachers and scientists use open data geoportals, which are developed by all mapping agencies. Some, but not all, of these portals have an English interface which facilitates their adoption by scientists from abroad. Dedicated sections within existing geoportals or agencies' websites can be added aimed specifically at schools and education. These specialised sections can include relevant manuals, data and services aimed at the specific target group, for example in Switzerland, see figure 1. Access can also be integrated within a teachers' digital working environment such as the case in Ireland where Ordnance Survey Ireland (OSi) have designed a specific section available from within the general purpose education platform Scoilnet (https://maps.scoilnet.ie/) or in France where the Edugeo solution is integrated within the general purpose Edutheque (https://www.edugeo.fr/). Data dedicated to a specific theme can also be produced, very often during collaborative research projects, such as the Shellfish Safety Data or Seabed Viewer designed with the Irish Marine Institute, see figure 3.

Figure 3: different thematic data products dedicated to specific communities in Ireland.

Specific events such as treasure hunts or escape games can also be organised. In addition, many organisations provide manuals, online training material, online courses, and professional training support, for example in Spain, https://cursos.ign.es, or France, http://cours-fad-public.ensg.eu/, such courses are normally in the local language. These above mentioned initiatives were found to have a high level of adoption and are well maintained.

Following this 2019 and 2020 survey, EuroSDR wished to identify possible new resources that could be achieved through a collaboration between European National Mapping and Cadaster Agencies (NMACs), with specific objectives including:

• to provide an Eduserv course on all educational resources, on how gain access and apply them, to understand data characteristics and to know where to obtain information about the data characteristics (metadata),

• to promote and accompany the usage of 3D or historical data,

• to establish links between national dataset portals, to support data discovery and reusage,

• to support pupils editing data or contributing to scientific data Europe-wide via Volunteered Geographic Information (VGI).

The following section outlines three new resources that fit the criteria outlined above.

Global, regional and national level spatial data for teaching and research in GIS in Estonia

The Department of geography of the University of Tartu (Estonia) uses global, regional, and national level data in teaching and in research. It benefits from one of the most advanced geoportals in Europe:

The Estonian Land Board Geoportal, see figure 4.

Figure 4: Geoportal of the Estonian Land Board, https://geoportaal.maaamet.ee/eng/.

The main requirements and limitations for teaching of the datasets in this portal are:

• good metadata that describes data lineage, Coordinate Reference System (CRS), attribute values etc. To enable international uptake, the metadata should be in English

• open formats -ideally the data is in open format or provided in several data formats, so the uptake would not be limited to proprietary software;

• different resolution/scale: national level data is often very high resolution which in teaching might be too "heavy" to process and therefore more generalised data is very useful e.g. Digital Elevation Model (DEM) models with 100m resolution

• should be easy download or Web Feature Service (WFS), however, with large datasets (more than 1GB) WFS can get slow Geographical Information Systems (GIS) have revolutionized the traditional geography classroom which was previously based on memorizing the world as a huge puzzle from large paper maps. This basic approach to learning can be boring for pupils and students, however maps have become better playgrounds thanks to GIS. It is now easier to create outdoor pedagogic activities involving the pupils, for example designing maps of a place that they will later visit and compare, or geocaching. To ease the usage of the French Geoportal data and services for classrooms, in 2010, the Édugéo platform was established by IGN-France in partnership with the Ministry of National Education, Higher Education and Research. For more than 10 years, expert teachers have succeeded in developing educational proposals adapted to classes from primary level to high school, and now higher education.

Students can display an urban map from 1960, circle the building, then superimpose the same map on it today and visualize at a glance what "suburbanization" means. Similar comparisons can be made with "coastal retreat" and "low density spaces", and they can prepare a report through the narrative maps module. Students can access statistics from the French National Statistics Institute and draw thematic maps, as shown in figure 6. In addition, students can visualise topographical data in a virtual and fun environment (Minetest) and experiment with 2D and 3D simulations of natural risks (floods, avalanches, volcanic eruptions). World data can be integrated in the Edugéo platform for the study of land change across the globe. For example southeast of Shanghai is an area of major land change with the Nanhui New City that covers about 74 square kilometers. The main feature of the new city is a circular artificial lake, visible from satellite imageries series starting in 2004. Its concentric structure can also be clearly seen. The building of the Donghai Bridge that connects the city to one of the largest shipping ports is also visible with its 32.5km long and six lanes of traffic.

Narrative threads can also be used to study through debating, for example the Beyrouth blast disaster, Brexit consequences on borders between UK and France or the Lubrizol factory disaster in Rouen. In the latter, encouraging students to get involved in a citizen debate nurtures their culture of risk.

Finally, IGN-France offers a library where each professor, student or anyone can use the weblink of a story map or another map product and insert in the support of their choice. In this library, resources are referenced using items from the official program of the ministry of education as shown on figure 7.

Figure 7: Registration of story maps on Edugeo through official education programs: to live in a big city, to live in a low density area, to live on the seashore, demography, limited resources, etc.

Discussion and perspectives

Approaches and experiences presented during the workshop, mostly developed in national contexts, were found to be relevant for all countries and could be adapted. Yet these approaches are not very intervisible and during the workshop wrap-up, participants insisted on the necessity to pursue exchanges.

It was found that opening up data is not sufficient to engage teachers. Swisstopo dedicated a specific section of its portal, centralizing all information relevant to this community. In the 5*S project and Edugeo, for a teacher to adopt a resource or open his classroom to the team it was necessary to describe how the proposed resources fit in the official educational program.

Teachers and scientists often need data from many providers, to study world-wide and more local phenomena.

The fast evolution of the field of GI makes it relevant to design teaching modules for those who learned GIS decades ago and who are not familiar with the new technologies, as was undertaken in Tartu University.

More specific topics for follow up events were identified. The first topic is how to improve the visibility of all existing approaches, tools, good practices, reusable resources, for example to design and maintain a dynamic survey.

The second topic for further work is to analyse user scenarios which would benefit from a European approach and distinguish what already exists to support them and what is needed and could be achieved in a joint activity. Examples of solutions that already exist include global solutions such as Google Earth Engine, OpenStreetMap, ESRI Land Cover products. As illustrated in the figure 8, each product has its advantages and disadvantages and is valuable to these communities. The third topic of importance is funding: what are opportunities. As reported by EuroSDR [START_REF] Bucher | EuroSDR Survey: Initiatives for providing data and tools for research and education[END_REF], national initiatives to engage with education communities are funded and maintained by national funds. Identifying funding for European or international projects necessitates considering other categories of funding.

The participants of the workshop convened to draft and submit to EuroSDR and AGILE a joint activity on « Geodata and tools for education and research».

Figure 1 :

 1 Figure 1: section of the Swiss open data portal dedicated to Schools. ...............................................

Figure 2 :

 2 Figure 2: rendering reference data for the Minecraft platform, and include a flood simulation. ........

Figure 3 :

 3 Figure 3: different thematic data products dedicated to specific communities in Ireland. .................

Figure 4 :

 4 Figure 4: Geoportal of the Estonian Land Board, https://geoportaal.maaamet.ee/eng/. ...................

Figure 5 :

 5 Figure 5: Structure of the 5*S project ...............................................................................................

Figure 6 :

 6 Figure 6: Thematic map drawn by students to display and analyze population densities in greater Paris. ..................................................................................................................

Figure 7 :

 7 Figure 7: Registration of story maps on Edugeo through official education programs ....................

Figure 1 :

 1 Figure 1: section of the Swiss open data portal dedicated to Schools.

Figure 2 :

 2 Figure 2: rendering reference data for the Minecraft platform, and include a flood simulation.

WP 2 -Figure 5 :

 25 Figure 5: Structure of the 5*S project: (a) WP1 entails school visits and 'Train the Trainer' events, while WP2 (b) encourages self-directed learning through AR in the SatelliteSkill5 app -Available for free on PlayStore and AppStore https://5sdiscover.maynoothuniversity.ie/downloads/

Figure 6 :

 6 Figure 6: Thematic map drawn by students to display and analyze population densities in greater Paris.

Figure 8 :

 8 Figure 8: Comparison of Land cover products, produced through state of the art Artificial Intelligence and sensors, on a city in South of France, one from the national mapping agency and one from Google.

Table of contents

 of Uuemaa E., Chartier M. "Geodata and Tools for Education and Research" AGILE Pre-Conference Workshop organized by EuroSDR, June 14 th 2022 -Vilnius, Lithuania (hybrid) Index of Figures ...

  Figure 8: Comparison of Land cover products, produced through state of the art Artificial Intelligence and sensors, on a city in South of France, one from the national mapping agency and one from Google. ..........................................

	1	INTRODUCTION
	Geographical data and analyses are a useful asset in several domains of education and research including
	geography, history, urbanism or environmental science, amongst others, from primary school to higher
	education and life-long learning. In the specific context of Europe, as more and more data (including
	geographic data) becomes open for all, it is crucial to ensure these users have the capacity to make the
	most of the wealth of this data.
	Reciprocally, from the perspective of data providers, education and research are particularly important
	application domains. They have the ability to link knowledge (production or dissemination) with data
	and adopt critical perspectives on this data.
	In this context, a half-day workshop was organised by EuroSDR during the 2022 conference of the
	Association of Geographical Information Laboratories in Europe (AGILE). It focussed on current
	experiences developed by EuroSDR members, mainly at national mapping agencies, as well as proposals
	stemming from AGILE research communities, to share experiences and visions on this topic. It also
	targeted possible synergies to interconnect existing approaches, usually national, and achieve cross-
	national solutions, in Europe and beyond.

: Space, Surveyors and Students -STEM Outreach

  ArcGIS for Schools programme and the SCSI Day in the Life recruitment programme offers the opportunity to combine a national network of volunteers with an existing data/training infrastructure. The top down approach develops and delivers satellite focussed content to students, with content tailored for students aged 13 -16yrs. Satellite themed content has been developed and delivered for Science, Geography and History. All content is made available to students through ArcGIS StoryMaps (Figure5a) with interactive components throughout to interest the students and keep them engaged. The 5*S partnership with the Department of Education in Maynooth University also opens the initiative to teachers and student teachers on both under/postgraduate teaching degrees there and enables co-creation of lesson plans tailored for different age-groups.

	4 5*SThe Departments of Geography/Education in Maynooth University, Ireland are leading a collaboration
	with Ordnance Survey Ireland (OSi -Irish National Mapping Agency), the Society of Chartered
	Surveyors Ireland (SCSI), Esri Ireland and Technological University Dublin to showcase satellites and
	survey data to students.
	5*S: Space, Surveyors and Students -STEM and the Sustainable Development Goals is a Science,
	Technology, Engineering and Mathematics (STEM) outreach project that builds on two existing national
	school-based programmes to target a national audience. A collaboration between Esri Ireland's award
	winning,

• WMS as a basemap could have the possibility to render layers separately which enables to use it more efficiently as a basemap in map design Important aspects include: proper metadata, Findability Accessibility Interoperability Reusability (FAIR) principles

[START_REF] Wilkinson | The FAIR Guiding Principles for scientific data management and stewardship[END_REF]

, and open access to the data with open standards. 5*S is funded by Science Foundation Ireland and is now entering its fourth year with demonstrations carried out to over 15,000 students, 250 teachers and over 2000 App downloads. 5*S has two main work packages (WP), see figure

5

:

WP 1 -Top Down:

Acknowledgement

The authors wish to thank participants for very fruitful exchanges as well as reviewers of this report for their thorough reading and constructive review, Audrey Martin from Technological University Dublin and Juha Kareinen from National Land Survey Finland.