.... in case you have not seen this: http://blogs.esri.com/esri/gisedcom/2014/07/18/investigating-land-use-change-over-time-with-the-usgs-historical-topographic-map-explorer/ Dan Walters Geospatial Liaison for ME, MA & RI USGS 196 Whitten Road Augusta, Maine 04330 207-776-1293 [log in to unmask] ----------------------------------------------------------------------- This list Maine GeoNews (GEOLIBRARY-L) is an unmoderated discussion list for all Maine GIS Users. If you no longer wish to receive e-mail from this list, you can remove your name and email address yourself at the this web address: http://lists.maine.edu/cgi/wa?SUBED1=geolibrary-l&A=1 Or,you may also request that your name be removed by sending email to: [log in to unmask]