Today in my Information Structure  class, our topic was Entity Relationship Modeling . While this is a technique that I have used frequently over the many years I have been designing Oracle databases, it was interesting to see a slightly different spin on the ideas. The second half of class was an exercise to take a stab (as a class) at coming up with a preliminary data model for a mythical genealogical database system.
While deciding if we should model PLACE as an entity, a woman in our class who is a genealogy specialist told us that only one database she has ever worked with tries to do any validation of location – but that it is virtually impossible due to the scale of the problem. Since the borders and names of places on earth have changed so rapidly over time, and often with little remaining documentation, it is hard to correlate place names from archival records with fixed locations on the planet. Anyone who has waded through the fabulous ship records on the Ellis Island website  hunting for information about their grandparents or great-grandparents has struggled with trying to understand how the place names on those records relate to the physical world we live in.
So – now to my daydream. Imagine if we could somehow work towards a consolidated GIS database that included place names and boundary information throughout history. Each GIS layer would relate to specific years or eras in time. Imagine if you could connect any set of archival records that contained location data to this GIS database and not only visualize the records via a map – but visualize the records with the ability to change the layers so you could see how the boundaries and place names changed. And view the relationship between records that have different place names on them from different eras – but are actually from the same location.
I poked around to see what people are already doing – and found all of this:
- Digital Earth  and it’s more recently updated counterpart Geospatial Applications and Interoperability  (GAI), a working group of the Federal Geographic Data Committee  that seems to now exist within the National Geospatial Program Office  of the USGS.
- GOS  – Geospatial One Stop which led me to the fabulous Lewis and Clark GeoSystems 
- The National Atlas  (also found off GOS) that includes a special History Chapter  (that starts to head in the direction I am imagining I think)
- GEOnet Names Server  (GNS) that provides access to the National Geospatial-Intelligence Agency’s  (NGA) and the U.S. Board on Geographic Names ‘ (US BGN) database of foreign geographic feature names (take this and add in a history element, and we are getting even warmer)
- GIS for the Humanities  – funded by a 2003 NEH Focus Grant , this project’s goal is “designed to create, and train faculty in the use of, mapping modules intended to enhance humanities courses”. I included this one because it gives a slice of the kind of teaching my dream GIS database could fuel.
- And two clearinghouses for information: the US National Geospatial Data Clearinghouse  and the United Nations Environment Programme / Global Resource Information Database (UNEP/GRID) Spatial Data Clearinghouse 
I know it is a daydream – but I believe in my heart of hearts that it will exist someday as computing power increases, the price of storing data decreases and more data sources converge. I do forsee another issue related to the challenges presented by different versions of borders and place names from the same time period – but there are ways to address that too. It could happen – believe with me!
- GIS and Geospatial Data Preservation: Research Resources 
- The Edges of the GIS Electronic Record 
- SAA 2006 Session 103: “X” Marks the Spot: Archiving GIS Databases – Part I 
- Google Earth, Historical Maps and Ideas on Context