The solution to the problem came in the form of a piece of Geographic Information Systems (GIS) mapping software. One of the PhillyHistory.org software developers used the software to overlay the historic Sesquicentennial map with a current Philadelphia street map. To ensure that the maps had the same orientation, he found several points that were in the same location on both maps- the intersections of Oregon Avenue and Moyamensing Avenue, Broad Street and Packer Avenue, and Broad Street and Pattison Avenue. By lining up the two maps using these three intersections, a reliable composite map of the two images was made. To download a copy of the map, visit Azavea Commons. Azavea is the software company who created PhillyHistory.org for the Philadelphia Department of Records.
This two-layer map proved to be a valuable tool for geocoding the Sesquicentennial photographs. Using the historic map, PhillyHistory.org staff could see that the Nuremberg section of the Exposition was located south of Packer Avenue and several blocks west of Broad Street but could not determine a more accurate location. With the two-layer map, however, it was easy to see that the Nuremberg area was located precisely at what is now the intersection of 18th Street and Schley Street. Thanks to the assistance of the software developers and Archives staff, the PhillyHistory.org team was able to geocode a large number of Sesquicentennial photos, making them easy to locate on PhillyHistory.org and providing an illustration of how technology can help us relate the past to the present.