Continued Experiments in the Storage, Discovery, and Use of GIS Resources for Art History
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Visual Resources Association Annual Conference March 26-29, 2019, Los Angeles Session: Mapping New Vistas: Employing Emerging Technologies into Your Visual Resources Services Presenter: Jon Cartledge
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Continued Experiments in the Storage, Discovery, and Use of GIS Resources for Art History
- 1. : Continued Experiments in the Storage, Discovery, and Use of GIS Resources for Art History Jonathan Cartledge Imaging Center, Smith College March 26th, 2019
- 2. Illustration courtesy U.S. Government Accountability Office
- 14. GeoNetwork Splash Page and diagram GIS resourceCataloging GeoserverGeoNetwork Discoverable & readable map Base Map
- 19. XML Import
- 27. Problems: Setup Use image from email to Dan
- 28. Problems: Documentation Image of Documentation
- 35. Final Thoughts
- 36. Jon Cartledge Digital Asset Specialist Imaging Center Smith College jcartled@smith.edu
Editor's Notes
- In the past few years, the Imaging Center at Smith College has been investigating the storage, cataloging, and classroom use of GIS maps. At previous VRA conferences, I have presented the basics of GIS cataloging standards, our experiments in storage with both a standard image database (in this case, an earlier version of LUNA) and a specialized GIS database – GeoServer. Today I’d like to talk to you about a pilot class project we conducted with volunteer students, and our investigation of GeoNetwork, an open source cataloging and searching platform designed to work with GeoServer. But first, a quick recap.
- Geographic Information Systems – a GIS map product is a digital map of geographic or spatial features, attached to database of features and their attributes. Each row of the database corresponds to a feature on a map. Features are placed on a layer – much like a Photoshop layer, and multiple layers allow you to create a visual representation of a geospatial phenomenon. These layers come from a wide variety of sources: satellite imagery, historical maps, or a GPS unit. GIS software allows you to import those features and assemble data layers.
- Each of these data layers can be re-used or altered for a new project in GIS software. The authorship is attached to each layer of features, but those layers can be reused in any number of combinations in GIS software.
- In the US, the most widely –used standard for GIS data is the Federal Geospatial Data Committee’s Content Standard for Digital Geospatial Metadata. (CSDGM). The categories of the structural standard break down in this way: Identification – these elements are what we’d consider standard cataloging data: title, originator, date, descriptive keywords, use constraints (copyright) as well as Progress (with fixed values of Complete, In Work and Planned) and Currentness_Reference (a free text description of when the data were gathered vs. when published). Data Quality – Data quality elements ask you to describe how sure you are the data are correct. Often these are free-text elements that describe, for instance, the margin of error between the actual coordinate location and the map. Spatial Data Organization – type of data used (vector, raster). Data is represented in two ways in GIS files. Vector data is point data that can act as individual points, or to create lines or polygons – the kind of data you might see on an architectural floor plan. Raster data is pixel data which can describe changes in data with value and hue. A map displaying different elevations areas in different colors would use raster presentation.
- Spatial Reference- Information about the coordinate system used, how precise the resolution of the asset and, very importantly, the projection. There are a number of ways you can turn a spherical (and not even perfectly spherical, at that) globe into a flat map. Each one has a set of algorithms that GIS software uses to create your map on the screen – but you need to select one, and that selection is stored with your map layers so the machine can properly read it.
- Entity and Attributes – A description of the asset database, with an explanation of the values you used, published codesets you might have used, and any non-standardized values that need explanation for the viewer. Distribution Information – contact and liability information of the distributor. Metadata reference – metadata standard used and contact information for the standard.
- These data live in an xml document associated with each layer of a GIS map product. Geospatial data are input by the device and descriptive data is input by the user (if they so choose) while they are creating the map.
- In the example here, you can see the cataloging entry options available in ArcGIS.
- In the mid-2000s ISO Technical Committee 211 was established to help develop the international standard to replace the CSDGM, ISO 19115, part of a suite of XML data standards for GIS data. ISO 19115 NAP (North American Profile) and its XML format guide ISO 19139, are relational, rather than CSDGM’s flat structure, with a set of 12 categories to describe your digital map. Being XML, the standard is extensible. It uses standard codelists for the higher level descriptive data and to describe each element type. Like Dublin Core, few of the elements are required. Crosswalks have been provided by FDGC to move the data. And, as you can see the categories roughly correspond, with some exceptions.
- Last year I spent some time working on storage and cataloging GIS objects with a set referenced maps of the Pukara archaeological site in Peru. What I needed was a storage platform that could put together the GIS “parts” and display them while storing them with cataloging. I tried a widely-used, open-source web application called Geoserver.
- Once you connect the layers to GeoServer, you can add an abstract and cataloging terms that refer back to the thesaurus source. You can’t push the XML metadata of your ArcGIS file into this cataloging screen – so I’d re-enter the information I’d already compiled. This means, among other things, you will need to define things like the projection so the layer is served up correctly.
- The rudimentary versions of your layers can then be served up through Layers Display, allowing you to preview the file, adjust the resolution, and zoom. It will also download the file as a KML object – a GIS protocol that allows you to use the file in concert with Google Earth
- I found GeoServer on its own to be problematic for discovery and cataloging. Display for resources both in search results, and the resource page is minimal. The lack of a web map service to create a basemap for the stored resources can make the image of the resource difficult to decipher, as you can see with this route map here – without context it could be anything from a shopping route to a trip around the continent. As for the cataloging, the need to re-enter data already in the XML metadata was both redundant and prone to error. The elements were minimal and not compliant to the ISO, and while you could reference the thesaurus you used to obtain a keyword – you could not connect to that thesaurus in any way.
- After consulting with Chris Gist, the GIS Specialist at UVA I turned to an open source cataloging and discovery platform designed to work with GeoServer, called GeoNetwork. The GeoNetwork application allows the user to find easy-to-view GIS resources with keyword and category searching and refining and allows the cataloger to create standard-compliant metadata records that can be connected to a number of resources.
- The discovery portion looks a great deal like the discovery portion of the image storage and retrieval software with which we are all familiar. After you perform a search and select a resource, you are taken to a page that offers an abstract, classification categories, download options, and a map that indicates the general area that the resource represents. In addition, you will see keywords, as well as the contact information, technical data and metadata information required by TC 211
- This is because GeoNetwork allows you to setup your cataloging templates with the metadata standard of your choice. You can choose from TC 211 suite of ISOs or Dublin Core. You can even upload other schemas.
- The elements for the standard you chose will automatically be setup when you create a new record.
- While Geoserver did not allow you connect with the xml data embedded with a GIS map, GeoNetwork will allow you to locate and upload this XML metadata into the GeoNetwork record.
- You will also find descriptive elements, including the option to pull keywords from a thesaurus
- GeoNetwork allows you to upload any thesaurus that is coded in the Simple Knowledge Organization System or SKOS format. This allows you to add any number of thesauri, or even customize your own thesaurus.
- SKOS is an application of the RDF framework that allows the terms of a thesaurus, as well as their relationship to other terms (for instance a broader term vs. a narrower term) within that thesaurus to be expressed.
- The Getty has been working to incorporate SKOS into their vocabularies as part of their as a part of their Linked Open Data pursuit.
- For this demonstration, Gregg Garcia, from the Getty, provided me with a subset of the AAT, which I was able to upload and use for providing keywords with surprising speed. The ease of this process made the possibility of providing the cataloger a number of thesauri from across disciplines or even creating a custom thesaurus seem achievable and pretty exciting
- Another feature of GeoNetwork is its ability to connect to a web map service to display with your GIS resource. As we saw earlier, resources stored in GeoServer will lack any sort of base map, but GeoNetwork is preloaded with OpenStreet Map.
- You can even set GeoNetwork to connect to any number of web map services – like those of the free web map services of the US Geological Survey or Natural Earth – a series of basemaps created by the North American Cartographic Information Society. The result is that each item stored in GeoNetwork is paired with a basemap of your choice to give the user context about the data they are viewing.
- While the abilities GeoNetwork made it a vast improvement from other solutions we’ve looked at for cataloging and discovery, it’s open source development was a source of a number of problems. Setup proved difficult, and our technologist, Dan Bridgeman, spent some time trying to find a version of GeoServer and GeoNetwork that would play well together, and with a Java servlet container. He eventually settled on earlier version of GeoNetwork running on Tomcat.
- Documentation seems to be created on a voluntary basis, which means that it can be rather spotty – as you can see here. Given the Imaging Center’s previous experience hosting in-house cataloging and delivery systems, we estimated that it would probably take 1 FTE to operate, update, troubleshoot, and follow the ongoing development of GeoNetwork. Given Smith’s current reluctance to use FTE to operate in-house applications, The implementation of this product would likely have to happen in partnership with another institution in our consortium.
- One of the reasons I’m so interested in the cataloging and retrieval of GIS data is that our Art Historians have had a long interest in maps. Given the fact that we’ve scanned every inch of Nolli’s Map of Rome, I could see a future in the use of American Academy of Rome’s GIS version of Nolli’s map. In the past few years, Harvard’s Digital Atlas of Roman and Medieval Civilizations has built up an impressive library of GIS layers of cited data for roads, ports, kingdoms – even Viking raid routes of the period.
- In an interest in giving our students the experiences they require to succeed in Art History, I partnered with the Spatial Analysis Lab and Professor Brigitte Buettner for a pilot in Smith’s Medieval Pilgrimages course. Students would have the opportunity to create an ArcGIS map and present it to the class in ArcGIS’s StoryMaps online tool for their final presentation, based on a Theoderich’s written account of a pilgrimage to the Holy Land. Two intrepid students volunteered for the project, Sophie Lei and Xiying Deng. I put together a couple of how-to documents for ArcGIS Online based on my own notes from my GIS course, and introduced students to Harvard layers. Tracy Tien from the Spatial Analysis Lab met with the students for a couple of training sessions and gave them an account in Smith’s ArcGIS account to access ArcGIS online to create their maps and StoryMaps to create the presentation.
- Sophie and Xiying went to work, and the result was a comprehensive site that followed the route of Theoderich and examined his sites by theme,
- allowed for real-world location of sites mentioned in the text
- and put these sites in context with images, text and videos.
- The resulting presentation was fantastic, but there were concerns once the dust had settled. Prof. Buettner was unsure how to grade such a project against a written paper and was concerned about the amount of time spent in learning the technology. The collaboration with Spatial Analysis proved difficult as their time was limited by other demands. That said, Sophie went on to use StoryMaps for another project that same semester, so while faculty and staff reception was mixed, student interest was quite positive.
- We are considering using Google MyMaps for another class pilot, with the hope that its functionality will match the presentation ability of StoryMaps without the training lift and interdepartmental coordination of ArcGIS Online. Which means the emerging need for storing and cataloging this material is an ongoing concern. Stay tuned!