Palaeontologia Electronica palaeo-electronica.org

The use of new web technologies for the analysis, preservation, and outreach of paleontological information

and its application to La Rioja (Spain) paleontological heritage

José M. Valle Melón, Álvaro Rodríguez Miranda, Félix Pérez-Lorente, and Angélica Torices

ABSTRACT

The present work proposes a project of digital preservation and dissemination ofinformation concerning paleontological sites located in the municipality of Enciso (LaRioja, Spain) by means of the regional SDI (Spatial Data Infrastructure) of La RiojaGovernment. In its original configuration, the system provides the location and generaldescriptive data of all the officially declared sites within the municipal boundaries.Besides, in-depth information is provided for one particular case–Valdecevillo site–forwhich the available datasets generated over the last 30 years (photographs, slides,plans, papers, etc.) were reviewed and sorted. Afterwards, a choice of this materialwas selected for digitization and online dissemination. Moreover, information has beenenriched with a three-dimensional (3D) model of the current state and a video report.The present work concludes with a reflection on the usefulness and the implications ofthis approach for the management of the paleontological heritage.

José M. Valle Melón. Laboratorio de Documentación Geométrica del Patrimonio – Universidad del País Vasco (UPV/EHU), Vitoria-Gasteiz (España). jm.valle@ehu.eusÁlvaro Rodríguez Miranda. Laboratorio de Documentación Geométrica del Patrimonio – Universidad del País Vasco (UPV/EHU), Vitoria-Gasteiz (España). alvaro_rodriguez@ehu.eus Félix Pérez-Lorente. Universidad de La Rioja, Logroño (España). felix.perez@ext.unirioja.es Angélica Torices. Cátedra de Paleontología, Universidad de La Rioja, Logroño (España). angelica.torices@unirioja.es

Keywords:palaeontology; ichnite; dinosaur footprint; SDI (Spatial Data Infrastructures); preservation ofinformationSubmission: 23 August 2018 Acceptance: 23 January 2019

Valle Melón, José M., Rodríguez Miranda, Álvaro, Pérez-Lorente, Félix, and Torices, Angélica. 2019. The use of new web technologies for the analysis, preservation, and outreach of paleontological information and its application to La Rioja (Spain) paleontological heritage. Palaeontologia Electronica 22.1.1T 1-10. https://doi.org/10.26879/918palaeo-electronica.org/content/2019/2422-digital-preservation

Copyright: February 2019 Society of Vertebrate Paleontology. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.creativecommons.org/licenses/by/4.0/creativecommons.org/licenses/by-nc-sa/4.0/

VALLE MELÓN ET AL.: DIGITAL PRESERVATION

INTRODUCTION

The Autonomous Community of La Rioja hasan exceptional paleontological richness that hasreceived scientific recognition nationally and inter-nationally. Some of its most characteristic featuresare the numerous sites of dinosaur footprints(Pérez-Lorente, 2017). Examples of communityinterest in this type of heritage are the existence ofnumerous marked and protected sites (Figure 1),the creation of interpretation centers, as well as theestablishment of cultural routes and even a themepark.

The present work focuses on the recovery ofexisting information about these sites, especiallythe information that remains unpublished and/or isdifficult to access. The objective is to develop strat-egies for its free availability, through the Internet,using technologies and standardized formats, mak-ing it henceforth interoperable. This objective aims,firstly, to enhance the knowledge and research ofthis heritage and, secondly, to comply with therequirements of European and Spanish legislationregarding the reuse of information and the dissemi-nation of data.

In the scientific community, there is an inter-esting debate on whether initiatives to promote theoutreach of heritage information are beneficial orcounterproductive in terms of the physical preser-vation of sites. Our general opinion is that they aremostly positive as they increase knowledge aboutthe heritage, make the local population aware ofthe interest of these places, and involve them intheir maintenance, facilitate the management ofthese resources by the administrations and theiruse by of other agents for tourism, social purposesetc. All these benefits undoubtedly increase thevalue of the paleontological heritage and, directly,have an impact on a greater social concern for itsphysical preservation.

However, it is clear that there will also becases in which the information must be managed ina more restricted manner, especially if it is consid-ered that there is a high risk of vandalism oranthropogenic degradation, and it is not possible toprovide additional measures that could alleviate it.

In this case, all the sites, compiled in therepository, are accessible without restriction, andincluded in hiking and family touristic routes pub-lished by the administration responsible for itspreservation and maintenance. The sites, analyzedhere, were already published in documents of theadministration and in scientific publications, so itwas not considered that referring them would sig-nificantly increase their exposure to deterioration.

The problem with these sites is that, on theone hand, their geographical location and spatialconfiguration are not clearly defined in the avail-able documentation, which makes it impossible forthem to be properly managed by administrations.Secondly, a large part of the relevant scientificinformation on these sites is scattered, in analogformat (in many cases), not classified, difficult toaccess, and does not have any maintenance, so itis susceptible to irretrievable loss.

The preservation of the results of paleontolog-ical research over time, (in order to guaranteeaccess to knowledge for future researchers, devel-opers of outreach products or the general public),is not only a priority that adapts to the Europeanand Spanish regulations, but must also be consid-ered as a moral duty. Preservation will allow that,even in the case of alteration or destruction of thefossil evidence, the information can still be studied.It should be noted that the future preservation andaccessibility of the raw records, such as photo-graphic collections, are of particular importancegiven the high vulnerability of the sites to be stud-ied, a subject already addressed by several

FIGURE 1. Two sites located in the municipality ofEnciso (La Rioja). Above, “Virgen del Campo”, below,“Icnitas-4”.

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authors (García-Ortiz et al., 2014; Leal et al.,2016). In this regard, experiences are known inwhich, based on archival data, new cartographicproducts and 3D models have been generated,allowing us to recreate previous states of sites thathave been degraded or disappeared severaldecades ago, thus being able to re-analyze them intheir original state (Falkinghan et al., 2014; Lallen-sack et al., 2015).

The preservation of information is a complexproblem, whose solution is not only to make datadumps. As has been repeatedly mentioned (Petru-zzelli et al., 2011), there are deep problems ofincompatibility of records and results between dif-ferent production teams (apart from other difficul-ties derived from the lack of contextualization,scarcity of primary data sources, etc.), whichgreatly limit the interoperability between research-ers and, ultimately, the re-use of paleontologicalinformation. In addition to guaranteeing the preser-vation of documentation, it is necessary to ensureaccess to it. This information must be operable inthe future, understandable and credible. Therefore,it is necessary the development and application ofa series of strategies and methodologies thatrange from design and selection of a metadatamodel, the application of controlled thesauri andvocabularies when making the descriptions, as wellas the choice of the file formats in which the digitalinformation will be stored and given access.

MATERIALS AND METHODS

The proposed action of this project is basedon legislation and recommendations regarding there-use of information (European Directive 2003/98/EC, afterwards modified by Directive 2013/37/EUas well as its subsequent development in the Span-ish legislation). It is related to initiatives such as theINSPIRE directive (Directive 2007/2/EC) for geo-graphic data, which includes the sites under thetheme "protected places" and which already hasinteresting examples of applications to heritage(McKeague et al., 2012) and geology (Janssen andKuczerawy, 2012).

The research is located in an area of specialpaleontological interest (the municipality of Encisoin La Rioja, Spain). The first step was a search ofthe existing materials (published information suchas scientific studies in journals and, essentially,unpublished information in the hands of research-ers). With all of this and with the collaboration ofthe Cartography Service of the Government of LaRioja, a pilot computer project was developedthrough the IDE (Spatial Data Infrastructure) of La

Rioja (hereinafter: IDErioja). This project allowsany user, freely, from any device connected to theInternet and intuitively, to access this informationusing an institutional web cartography server. Like-wise, a methodology has been designed thatmakes it easier to continue incorporating the newdata that is obtained, both from new research andrecovered from studies already carried out, so asto advance towards an integrated system of pale-ontological information.

Figure 2 shows the general scheme of theproposal implemented by our work team. It isbased on the information available to variousresearchers on a set of sites chosen by the crite-rion of being recognized and protected. On thesesites the available information is studied, the onethat is considered of interest for its publication isselected, and it is linked to its geographical position(previously revised). This information is preparedfor its dissemination through the Cartography Ser-vice so users can access it. Likewise, the negotia-tion process between the agents is included inorder to ensure the rights of reuse of the informa-tion that will be provided.

DEVELOPMENT

As indicated, this is a pilot project whoseobjective is to develop a data structure for paleon-tological heritage management through an SDI.Therefore, for the time being, it has not beenincluded exhaustive information on all the sites;that is to say, so far we have introduced someexamples that allow analyzing the use and poten-tial of the proposal. Later, to the extent that boththe administration and the rest of the potentialusers are able to use this resource and value itpositively, it is expected to expand it with moreinformation based on new work being done in thesites and the availability of means to recover infor-mation from the archive. In spite of this, it is alsonecessary to indicate that the web tool is opera-tional and that it provides all its functionality for theavailable sites.

The information is grouped at the "site" level.In this regard, it was necessary to decide whichsites would be introduced, at least in relation totheir position and name in IDErioja. The bib-liographic search revealed the existence of 32paleontological sites located in the municipality ofEnciso, as well as others that are known by neigh-bors but remain unpublished. Of all of them, theyonly have an official definition of position and namethe 15 that were included in the BIC (Asset of Cul-tural Interest) declaration through Decree 34/2000.

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One of the fundamental tasks of this projecthas been to clarify the responsibilities and rightsrelated to the information, as well as to provide thedifferent actors with the legal coverage to use it. Tothis end, appropriate agreements have been estab-lished between the creators of the information, thephysical depositories of the data (photographs,plans, etc.), those who have intervened in its pro-cessing (digitization, uploading to the servers) andthe administration that offers the storage andaccess service through the SDI node.

Once the legal support was established, itwas possible to attend to the technical design ofthe solution, which included the definition of thedatabase, the selection of the information to betreated, the metadata schemas, the controlledvocabularies to be used, the characteristics of thecopies that would be supplied (resolution, formats,types of use licenses, etc.).

Due to its special interest, among the differentaspects of the technical design, we will now stop atsome regarding the geographical location of thesites. Indeed, localization can be the cause of con-flicts in any information management system, and

even more so in the case of paleontology, in whichthe sites are part of the terrain itself. Also dis-cussed is the specific case of the Valdecevillo site.

Geolocation of the Sites

Geographic location is essential within an SDIsince it is the basis for representation and interop-erability with other layers of geo-information suchas the land registry maps, communication routes,protected spaces, etc. Therefore, the location mustbe obtained with the margins of precision and rep-resentativeness appropriate for the uses that areintended to be made. This issue is controversialsince, in the absence of precise delimitations withofficial rank, each new author who studies the sitestends to create their own delimitations, which gen-erates a state of arbitrariness and lack of coher-ence when locating the data. Also, some locationscorrespond to old works that were obtained fornon-cartographic purposes, so it is not uncommonthat the available coordinates indicate a place at aconsiderable distance from the site itself.

In view of this situation, the following criteriawere adopted when defining the position of a site:

FIGURE 2. Scheme showing the agents involved in the work, the transformations and the movement of the informa-tion.

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- If available, use the positions that are officiallypublished.

- In the case of multiple delimitations (sometimesin disagreement), indicate the position that bestdefines, within the cartography, the location ofthe sites and define what the criteria or scien-tific rationale is/are for making the change

- Maintain the traceability of the performed coor-dinate transformations (for example, conversionbetween reference systems and/or projections,passing the reference as a UTM grid to the defi-nition as a perimeter, etc.).

- In any case, do include a note with the accu-racy of the geo-location. Moreover, state thereference system and cartographic projectionthat are used.

Consequently, the collection of coordinatesstarted from the BIC definition of the Enciso sites.Nowhere in the decree is the geodesic referencesystem used indicated, although, in the case of theyear 2000, it might be understood that it will be theone used in the official cartography of both theNational Geographic Institute and the Army Geo-graphical Service by that date, that is, the denomi-nated as ED50 (European Datum 1950). Atpresent, the current reference system is the onenamed as ETRS89 (European Terrestrial Refer-ence System 1989), and it is this one in which theofficial cartography is referred and, therefore, theone that uses the Spatial Data Infrastructure of LaRioja (IDErioja) in which the results of this workwere deposited. For this reason, it was necessaryto carry out the transformations between both sys-tems (the difference in this area is about 200 m).

Another problem is that the sites are superfi-cial entities but the official definition that appears inthe BIC statement only provides their positionthrough a point. To solve this discrepancy, in all thesites, except in Valdecevillo as will be seen later,polygons have been generated in the form of asquare of 4 m2 (2 x 2 m) centered on the previouslycalculated point. Of course, these polygons do notrepresent the site correctly, but at least allow it tobe included in the database as polygon entities andincorporate the related information. When, in thefuture, the official geometry corresponding to thepolygon is available, it will only be necessary toupdate the geometry of the database while keepingthe rest of the information. Obviously, this way ofproceeding must be complemented with an attri-bute that is associated with each perimeter andthat indicates to the user what is its validity, that is,according to what criteria this perimeter has beendetermined and what legal support it has.

Of course, the representation as polygonsdoes not prevent, in a complementary way, alsohaving identification in the form of a point. Forexample, this one can be used to place an icon inthe small scale visualizations. In order to verify thepositional accuracy of these polygons, the differ-ences with respect to the actual position of thepaleontological remains have been analyzed oncartography with discrepancies of up to 50 m beingdetected. It is clear that the coordinates that weredefined for the BIC declaration are not suitable forinclusion in the IDErioja geographic databases,given that they do not define the sites with suffi-cient precision or detail. As a result, they do notallow exploiting the potential of geographic man-agement, that is, inquiries such as in which cadas-tral plot a determined site is located or at whatdistance from a certain road. However, despite allthese deficiencies, these coordinates are the onlyones that have some type of official recognitionand, therefore, the only ones that should be inte-grated into the database of the Government of LaRioja. Otherwise, we would be operating with geo-metric entities that have no meaning for legal pur-poses, which would cause multiple problems whenperforming management tasks. The solution to thissituation would be for the Government of La Riojato promote a new work to delimit the sites and togive them legal validity through the correspondingupdate of the BIC declaration. Obviously, this revi-sion of the perimeters should be obtained underthe advice of technicians in paleontology thatwould establish the zones to be protected, whichshould include both the surfaces in which there arevisible remains and the areas of presumption that,equally, deserve to be taken into consideration. Inany case, regardless of how the site perimeters aredefined, it must be borne in mind that the defininggeometries of the sites must indicate the procedurefollowed to obtain them, the reference systemused, the precisions achieved, and the technicalcartographic criteria that guarantee their traceabil-ity and define the quality of the geographic data.However, while awaiting for this new definition ofperimeters to exist, it is necessary that the man-agement system begins to function and, for this,despite its defects, it is necessary to rely on thecoordinates of the BIC declaration of the year2000.

Geographic Names

The location of a geographical element can bedone both quantitatively by identifying with coordi-nates in a given system and by means of topon-

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ymy. Geographical names can refer to locationsthat are extremely local or as wide as a continent.As was done with the coordinates of the sitesunder study, the quality of the toponymical defini-tion of the same was analyzed, for which both theofficial gazetteers and the cartographic series ofthe National Geographic Institute and the Geo-graphical Service of the Army and publications onlocal toponymy. In this aspect we must indicate thatthere are two erroneous place names in the BICdeclaration that, in the present work, have beencorrected, since their confusion has been draggingalong the successive publications that cite them,and it was considered that maintaining the erroronly contributes to its persistence.

Valdecevillo Paleontological Site

The Valdecevillo site is one that was first stud-ied in La Rioja and on which more research work ofdifferent types has been developed (Casanovasand Santafe, 1974; Casanovas et al., 1989; Valle,1993; Díaz-Martinez et al., 2010). For this reason ithas been chosen to carry out an exhaustive dumpof the existing information about it, thus serving asa test of implementation and example of the poten-tial of the generated product. With respect to its

geographical definition, instead of the 2x2 m chartthat was obtained from the definition of the BIC, aperimeter obtained in the field by GNSS observa-tions has been used and serves as an example ofhow these definitions would be once it is decided toupdate those corresponding to each site .

The information available on this site includessketches of the excavations, plans, slides, andreports, as well as other documents of very differ-ent types, such as brochures, tourist guides, post-cards, and newspaper articles. All these materialshave been digitized and incorporated into thearchive (Figures 3-4).

The digital files have been enriched by theincorporation of metadata so that regardless ofwhere they are located and how they are subse-quently redistributed, they have information abouttheir content, authorship, rights, and purpose oftheir creation. The schemes used depend on thetype of file, for example, a combination of Exif andIPTC for photographs or Dublin Core for text docu-ments and plans. If internal metadata are notincluded in each document, there is a risk of repro-ducing the same problems that have been found inmany of the analog images (paper, slides, etc.) thathave been located among the documentation pro-

FIGURE 3. Photogrammetric survey of one of the tracks (scale 1:2.5). Initially published in Valle (1993) in black andwhite. The version presented here is in color, offers more detail, and retains the metric (since it is obtained from theoriginal CAD file while the copy of the article was a photocopy).

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cessed for this project but that, having no referenceto their context, they have had to be discarded,given that it was impossible to know what they arereferring to and what they can be used for in thefuture.

On the other hand, the paleontology layer thatis available through IDErioja has metadata accord-ing to the ISO 19115 scheme, which allows incor-porating general project information. In addition,this scheme has some particular characteristicsthat make it particularly suitable for describing geo-graphic information. In particular, this schemerequires that the reference and coordinate systemsused are indicated (thus eliminating the cases ofambiguity as the aforementioned between theED50 and ETRS89 systems). Also, it incorporatesindicators of data quality (such as geometric preci-sion) and a description of the sequence of pro-cesses that have been carried out during theprocessing of the information. In this way, the user

knows the traceability of the data (called “lineage”in the terminology of ISO 19115).

Since the sites are part of the territory, theyundergo changes due to anthropic and naturalactions. In addition, these are study areas thatchange as the excavations are extended, resto-ration or musealization actions are undertaken,new analyses are carried out with new techniques,etc. Therefore, it is interesting to consider that thedatabase can incorporate new information from thesites over time and that this fact allows analyzingand managing them taking into account their tem-poral evolution. In the case of the Valdecevillo site,new products have been generated that reflect itscurrent state, specifically, a three-dimensionalmodel obtained by photogrammetric methods (Fig-ure 5) and a video taken from a drone (Figure 6).

RESULTS

The design of the specific database for pale-ontology was made from the previous databases ofthe Ministry of Culture and in collaboration with thestaff of the Geographical Information Systems andCartography Section of the Government of LaRioja (IDErioja) for the aspects of implementation.The first decision to be made was to define whatwould be the unit of action for the management ofpaleontological information, since information onsites, trackways, and footprints is available. Pre-cisely, each one of them responds to a spatialtypology that can be collected in the IDE, so thesites can be considered superficial elements, the

FIGURE 4. Same footprint of the previous figure, asrecorded during its excavation in 1984. Image obtainedby digitizing the slide film (analog format).

FIGURE 5. Interactive virtual model of one of the track-ways of the Valdecevillo site generated by photogram-metry. Perspective view of a track with an approximatesize of 1 m with by 4 m long.

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traces linear elements, and the traces punctualones.

During the first weeks, the advantages ofeach one of them were analyzed and even the pos-sibility of the combination of the three types. It wasfinally agreed that the best option consisted ofgrouping at the site level, but coding the name ofeach document associated so as to maintain trace-ability in terms of footprint and trackway, since thisinformation is collected for each of the ichnites.The design was contrasted with IDErioja to verifyits viability. Some adjustments and improvementswere made, consisting in the non-implementationof some fields, adding characters to others andsuppressing the obligatory nature of the inclusionof information in those fields for which said infor-mation was not always available. The generatedlayer is accessible within the IDErioja catalogue. Italso has a specific thematic viewer that only showsthis information on the base cartography or theupdated orthoimage (Figure 7). This viewer can beconsulted on any device with Internet access,either in the office or on mobile devices (in whichcase, the possibility of geolocation on the map isoffered so that it can be used as a guide for thevisit). The screen shows an interactive map withthe location of the sites, in addition, it allows thedownload of the information (vector elements andassociated attributes), as well as the realization ofsearches by site, municipality, or value consignedin the attributes. Once a site has been selected, itsattributes are displayed (code, name, description,geological age, lithology, protection, type ofaccess, signage, bibliography, etc.), as well asaccess to associated documents and photographs.

On the other hand, the following OGC (OpenGeospatial Consortium) standard services havebeen created for the search of maps (WMS - WebMap Service - https://www.opengeospatial.org/

standards/wms) and for the download of entities(WFS - Web Feature Service - https://www.open-geospatial.org/standards/wfs).

These services are accessible directlythrough a web browser. Also, most GIS and geo-graphic viewers (such as Google Earth®) allowtransparent linking to the user and the visualizationof their content together with other layers of infor-mation that are either linked to other OGC servicesor locally available (for example, in SHP-shapefiles) (Figure 8).

CONCLUSIONS

The public availability of abundant, ade-quately contextualized and quality information onpaleontological sites for researchers, the adminis-tration and the public in general will not only allowtheir valorization but also the promotion of newsocial and economic activities. However, at thepresent time, this information is scattered, in manycases, within the personal files of the researchersthemselves and in analog formats (paper, slides,carbon copies, etc.) that are not digitally adapted tooutreach standards.

All this prevents, to a large extent, theirexploitation, and increases the risk of loss of infor-mation in a short period of time. By providing thisinformation via the Internet through the Cartogra-phy Service of the Government of La Rioja, it ispossible to place it in its spatial context, since it isdirectly integrated with the rest of the availabledata for the province (relief, hydrography, trans-

FIGURE 6. Video obtained with a drone in which a flightis made through the site.

FIGURE 7. Interactive thematic map with paleontologi-cal information, available on the web cartography serverof the Government of La Rioja (https://www.iderioja.lari-oja.org/vct/index.php?c=3373703472624e584d3833363864336167334f6b64513d3d&t=3.

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port, urban centers, natural resources, etc.). Inaddition, it opens the possibility of using this infor-mation from mobile devices so it can be used forthe creation of tourist and cultural routes and prod-ucts that allows society to connect with this extraor-dinary paleontological heritage. However, thedeclarations of Asset of Cultural Interest of thesites subject to management and protection needto be updated. This update needs to address espe-cially its geometric definition. In fact, given the cur-rent context of geospatial information it iscompletely inappropriate that the definition of pale-ontological sites still corresponds to point entities,defined in ambiguous coordinate systems and withuncertainties of several tens of meters. As a result,a proposal for the management of paleontologicalheritage information of La Rioja from the regionalSDI is offered. The approach develops in detail a

pilot site (Valdecevillo) and, more generally, all thesites of the municipality of Enciso that are declaredas BIC. The generated web application, at thepresent time, is being analyzed by different typesof users in order to contrast its usefulness andpoint out the possible modifications to be intro-duced.

ACKNOWLEDGMENTS

This work had the support of the Institute ofRioja Studies (Government of La Rioja) through the2015 grant "Research Projects of Rioja Thematic".Likewise, we would like to thank the IDErioja stafffor their collaboration and excellent disposition, inparticular, G. López García, and E. PascualPinedo.

REFERENCES

Casanovas, M.L., Fernández, A., Pérez-Lorente, F., and Santafé, J.V. 1989. Huellas de dinosaurios de La Rioja. Yacimientos de la Virgen del Campo, La Senoba y Valdecevillo. Instituto Estudios Riojanos de Ciencias de la Tierra (12).

Casanovas, M. L. and Santafé, J.V. 1974. Dos nuevos yacimientos de icnitas de Dinosaurios. Acta Geológica Hispánica, 9(3):88-91.

Díaz-Martínez, I., de Landaluce, E.G.O., Lorente, F.P., Sáinz, A.M.C., and Vela, A.J. 2010. Virgen del Campo, La Senoba y Barranco de Valdecevillo: tras las huellas de los dinosaurios de Enciso. Cidaris, 30:339-347.

FIGURE 8. GIS environment in which the paleontological information is linked to the orthoimage of La Rioja (both asWMS services). Information is visualized together with a vector file (SHP format) with the perimeters of the Spanishprovinces.

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Falkingham, P.L., Bates, K.T., and Farlow, J.O. 2014. Historical photogrammetry: Bird's Paluxy River dinosaur chase sequence digitally reconstructed as it was prior to excavation 70 years ago. PLoS One, 9:e93247. https://doi.org/10.1371/journal.pone.0093247

García-Ortiz, E., Fuertes-Gutiérrez, I. and Fernández-Martínez, E., 2014. Concepts and terminology for the risk of degradation of geological heritage sites: fragility and natural vulnerability, a case study. Proceedings of the Geologists' Association, 125:463-479. https://doi.org/10.1016/j.pgeola.2014.06.003

Janssen, K. and Kuczerawy, A. 2012. Increasing the availability of spatial data held by public sector bodies: some experiences and guidelines from the OneGeology-Europe Project. IJSDIR, 7:249-276.

Lallensack, J.N., Sander, P.M., Knötschke, N., and Wings, O., 2015. Dinosaur tracks from the Langenberg Quarry (Late Jurassic, Germany) reconstructed with historical photogrammetry: evidence for large theropods soon after insular dwarfism. Palaeontologia Electronica, 18:1-34. https://doi.org/10.26879/529

Leal, A.S., Dionisio, A., Sequeira Braga, M.A., and Mateus, O., 2016. The long term preservation of Late Jurassic sandstone dinosaur footprints in a museum environment. International Journal of Conservation Science, 7.

McKeague, P., Corns, A., and Shaw, R. 2012. Developing a spatial data infrastructure for archaeological and built heritage. IJSDIR, 7:38-65.

Pérez-Lorente, F. 2017. Developments and contributions in the study of La Rioja dinosaur footprints (Spain). Spanish Journal of Palaeontology, 32:171-184.

Petruzzelli, M., Razzolini, N., and Francescangeli, R. 2011. Proposal for an uniform data standard for ichnological 3D tracking and post-processing. Rivista Italiana di Paleontologia e Stratigrafia (Research in Paleontology and Stratigraphy), 117.

Valle, J.M., 1993. Metodología y resultado del levantamiento por fotogrametría terrestre del yacimiento de huellas de dinosaurio de Valdecevillo en Encisco (La Rioja). Zubía, 165-186.

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