Overlays for the Day: D.C. Government Online

Posted on Posted in Cities, Mashups, Urban Informatics

The D.C. Government has made significant strides in making a host of data sets available. This has resulted in a number of web-based applications related to all number of city services: parking, environmental services, biking, etc. Leveraging private developers is a great way for cities to build a repertoire of online applications.

While current data such as parking spaces is relevant to everyday activities and iPhone users, the D.C. government has also made available .tif files of historic maps, something that we are interested in for our research. Developing some overlays of historical and current data reveals a few intriguing insights. Though probably well-known to the avid D.C. or urban historian, most D.C. residents would probably not know that the Potomac River was once quite a bit larger, for land was reclaimed around Hains Point, the Tidal Basin, and the Jefferson Memorial. Incidentally, DC Vote also has a host of historical maps available online, as well.

Here is a map published in 1793 for the proprietors J. Good (originally published in Literary magazine and British review, Jan. 1793).

You can see the original boundaries of D.C., as defined by L’Enfant. If we zoom into central D.C., we can see in greater detail the Potomac River basin.

Now, we can overlay some current data sets to see how much land reclamation and land-use changes affected the development of urban areas. Here you can see the current bodies of water overlayed on the Good Plan map, noting the old and new Potomac Rive boundaries.

And, finally, we’ll overlay the current roads within the District, which have remained consistent, if perhaps containing a few more potholes, since the inception and construction of the city.

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