ProQuest’s Sanborn Maps Geo Edition (1867-1970) is a geo-referenced version of the Sanborn collection for the US, already purchased and available at http://sanborn.umi.com/.
The Geo Edition currently contains geo-referenced Sanborn maps from 20 large US cities (none in Iowa, closest is Chicago). Geo-referencing the maps enables layering of the same location from earliest to latest Sanborn map. Within this program, the geo-referenced Sanborn maps can be superimposed over the modern street, satellite, and hybrid layers found in Google maps.
Searching is available by address or GPS coordinates. Geo Edition maps can be saved in either JPEG or Geotiff format (the latter retains its georeferencing and can be added to a GIS program such as ArcGIS).
By the end of 2010, ProQuest plans to complete the georeferencing for the other city / town maps from states represented by the 20 initial cities. After that, work will begin on georeferencing maps from all remaining states, but no state-by-state time table exists.
Please send additional comments to Mary McInroy.