topoView, philly change gif
![Comparing modern-day Philadelphia to the historical map of the area in 1891 gif](https://d9-wret.s3.us-west-2.amazonaws.com/assets/palladium/production/s3fs-public/styles/full_width/public/thumbnails/image/topoView%2C%20philly%20Change%20gif%20-%20July%202017.gif?itok=OOkVtH4P)
Detailed Description
Comparing modern-day Philadelphia to the historical map of the area in 1891. TopoView lets users easily visualize changes to areas that were mapped by the USGS throughout history.
Comparing modern-day Philadelphia to the historical map of the area in 1891. TopoView lets users easily visualize changes to areas that were mapped by the USGS throughout history.