GIS, or Geographic Information Systems, is a field of study that combines geography and database technology to allow the creation of digital maps. Map features like roads, creeks, houses, or parks, are all stored in the database, and can all be graphically displayed on a map.
Whether we know it or not, most of us use GIS maps everyday – when we’re driving in our car with a GPS Navigation System, when we check the local weather radar map, or when we look anything up on Google Maps. GIS maps are used extensively in business and government too – whether a company is mapping out its office or retail locations, or a local government is planning a new subdivision.
Historical GIS takes this concept a step further. Most of the GIS maps mentioned so far only deal with the present day landscape, but there’s a whole history of landscapes that are largely left unmapped in GIS.
For example, your town might have a main street with a row of houses and shops that appear on Google Maps, but what if you wanted to know what that street looked like 50 years ago? Or 200 years ago? There may be some sketches or hand-drawn maps in the local library that could help, but say you wanted a map that transposed those historic features on a modern map? That’s where Historic GIS can help by providing additional layers that capture time as an attribute. There might be one house, say, that existed from 1720 to 1850, and another that existed from 1720 to present day, and a bunch more that were built in the 1950′s. If the data was set up properly, you could create a snapshot map for every year since your town was founded.
Temporal GIS and Animated Maps are relatively new concepts that build upon the idea of historical GIS. The last section discussed the idea of snapshot maps. Now, if you were to take those snapshots and string them together in a time sequence you could actually see the growth and development of a geographic location as features (in this case structures) come and go over the years.
This idea can also be applied to historical events, like say, a military battle. If the movement of troops can be recorded in GIS as a sequence of events of snapshots over a number of hours, they can also be strung together or animated in a way that would allow the map user to see the battle unfold.
This concept of animated battle maps has been developed and implemented by Sean Moir. Sean has also created the other mentioned type of temporal GIS map that demonstrates the growth and development of a region over a span of years. The results can be viewed on this website.