The Post Road data was created during my time as a Tri-college digital humanities intern with the Viral Texts Project at Northeastern University. I used two maps  from the Library of Congress, both created by the official topographer to the Post Office Department, Henry A. Burr. Burr was the first topographer for the Post Office Department. Before, the government would employ commercial and private firms to create maps for the Post Office Department, but with Burr’s position it was his responsibility to make all maps relating to postal business. (http://www.archives.gov/research/post-offices/locations-1837-1950.html)  Both maps are entitled “Disturnell’s new map of the United States and Canada showing all the canals, rail roads, telegraph lines and principal stage routes.” The first is  from 1850 (http://www.loc.gov/item/2012593337/). The second, from 1851 (http://www.loc.gov/item/gm70005366/).  First, I georecitified (http://www.loc.gov/item/2012593337/), using a reference map of the United States from the National Oceanic and Atmospheric Administration (NOAA), I matched up the different cities on the Burr map to the geocoded cities found through the basic geocoder in ArcMap, which was placed over the NOAA map. After there were at least two different control points per state,  I used the spline projection and georectified the image. The control points I used were cities found on both maps. For example, Charleston, South Carolina would be matched on the Burr map to its present location. Then, using this newly georectified map, a new shape layer, a polyline, was created and was named “post roads.” Using the key on the georectified map, the stagecoach roads were found and the new attributes were added to the shapefile “Post Roads.” Over every stage coach road, a line was drawn to the closest specification possible. Once completed, there were some questions as to whether some roads were post roads because there were colors on top of the lines on the map not referenced in the key. I was told, when I called the Library of Congress,  Henry A. Burr did not finish painting the map, hence, the indiscriminate colors over some lines on the map. I then matched up this georectified map to another map by Henry A. Burr without color from one year later (http://www.loc.gov/item/gm70005366/). I used the same procedure as above to georectify this map and double checked my newly created post roads later. Once checked, the data was modified accordingly and made ready for public use on ArcGIS online.

 

To download the data in shapefile format:

To view on a larger map: http://bit.ly/1oTa2AH (click on the map thumbnail)

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Post Roads by Laura Newman Eckstein is licensed under a Creative Commons Attribution-NoDerivatives 4.0 International License.
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Categories: Maps

Laura

Laura Newman Eckstein is the Judaica Digital Humanities Coordinator a the University of Pennsylvania. She is an enthusiastic cartophile, a digital humanities lover, and creative spirit. Currently, Laura lives in Philadelphia, where she enjoys spending her free time exploring the city with friends, reading books, and playing with her landlord's dog.