In this blog and in our book, we have reviewed many geospatial data portals. One of the oldest and yet most useful of all regional or state portals is that of the Texas Natural Resources Information System, or TNRIS. Indeed, TNRIS predated digital spatial data, for it was founded in 1968, housing paper topographic and geologic maps and aerial photographs for years before hosting digital spatial data. TNRIS allows searches by county or by data theme. If one zooms in on a the statewide map with county boundaries, the familiar USGS 7.5-minute grid is displayed, from which one can download such data as digital raster graphics, elevation, wetlands, geology, and historical and current satellite imagery. Statewide themes include bathymetry, land cover, soils, census data, transportation, and many others. Metadata is not only available but it is conveniently packaged, and the site doesn’t burden the data user with needless frills and fancy ways to download–it is, in my view, what a data portal should be–with the ability to quickly go in and get what one needs, in a variety of formats.
As GIS technologies have evolved, the TNRIS portal has evolved as well. One of the most innovative and useful sections of their site is its online mapping services. Here, high resolution imagery (30 cm in many places), land cover, and other themes are hosted as ArcGIS services and OGC WMS services. The site conveniently enables the data user to preview the services on their website or to copy the URL for the service so that it may be used in ArcGIS Online. Therefore, not everything from TNRIS needs to be downloaded–a growing amount can be streamed.
Texas is an excellent location for other useful data portals as well: The General Land Office hosts data on habitat, minerals, oil and gas, and other themes. The Texas Commission on Environmental Quality hosts data on air and water quality, toxic hazards, and other layers. Texas Parks and Wildlife hosts data on bays, ecosystems, trails, and wildlife management areas. And other gems exist, such as the railroads and other data hosted by Entergy on the Texas Site Selection Center.
A section of the Texas Natural Resources Information Systems geospatial data portal.
Maryland’s mapping and GIS “iMap” data portal takes an innovative approach to serving data. It allows the user to zoom to a specific area on the map and then conduct a data search for that specific area. Yes, other sites have done this for years, but the Maryland data portal uses a dynamic ArcGIS Online map to launch searches. In addition, the 20 data categories listed–from agriculture to demographics, health to imagery, structures to weather–are rich in content, and the data user is offered numerous data formats to receive the data. The site also goes the extra distance by providing step-by-step instructions on how to add web and WFS services, how to geocode, how to join data, and how to cartographically display results.
The GIS data portal is run by the Geographic Information Office (GIO), and by collaborating with partners, it seeks to “provide access to a large collection of data via the Maryland iMap that can be leveraged for use in many applications and analyses.” The GIS data portal is a part of the state’s open data portal, which claims to be #1 in the USA for its commitment to open data.
We are honest in our book and in this blog about describing data portals that seem to be there “just for show” and that had no input from GIS professional staff. The Maryland iMap portal, by contrast, is quite innovative, extensive, and GIS-user friendly, and seems to be a good model for other organizations to follow. Such portals do not appear overnight, and this is obviously the product of a good deal of collaboration among government, private, academic, and nonprofit organizations,
Some key spatial data from longstanding data portals are making their way onto platforms such as ArcGIS Online. One of these is the data from the Iowa Geographic Map Server, served from the Iowa State University GIS facility. The data set, searchable on ArcGIS Online via the keywords “Iowa Geographic“, is one of the finest examples of the holdings of a state data depository in an easy-to-use format.
The data available includes aerial photographs from the 1930s, 1950s, and then every decade from the 1970s onwards. Also included are an atlas from 1875, a general land office survey from the 1800s, a hillshade from Lidar data, the public land survey system, civil townships, and watershed boundaries. Changes in agricultural practice, urban forms and size, river meanders, and much more can be explored via this map. In addition, one can add the individual layers to one’s own map by pointing to the server URL found in the metadata for each layer. That the metadata are well populated is another reason that the data portal has long been one of my favorites. If one needs to download the data, those data sets are still available via the data portal at Iowa State University on http://ortho.gis.iastate.edu/. While even more data are available via the data portal itself at Iowa State University, it is wonderful to be able to quickly browse a subset of the data via the ArcGIS Online map. ArcGIS Online contains tools such as making layers transparent, adding map notes and bookmarks, and the ability to use the Iowa portal layers as a backdrop for one’s own data. In addition, as a teaching and research tool, the way the data are served in ArcGIS Online allows land use changes to be quickly observed and measured without having to download each layer and loading them into desktop GIS software.
As data from portals such as the Iowa Geographic Map Server migrate to platforms such as ArcGIS Online, the data user will have additional ways to access that data. It takes a commitment from data providers to serve their holdings onto these platforms, but data users in government, nonprofit, industry, and academia will all benefit. Learn more about data portals, data platforms such as ArcGIS Online, and data types in our book The GIS Guide to Public Domain Data, and keep an eye on this blog.