The earth is constantly changing. New manmade structures and transportation routes are built everyday. Water and landscapes change over time though the process of erosion and weather. Most maps today are out of date and need to be revised according to current aerial photography, satellite imagery and field collection. Comapanies today are working hard to keep their data as up to date and accurate as possible. For example, the 8th edition of the National Geographic Atlas had more than 15,000 revisions. GDM can bring high quality and accurate revision services to in a reasonable amount of time, for a competitive price.

GDM’s Photorevision (PR) experience includes revising 4,400+ hydrography quads for the entire state of Texas based on PR guidelines and specification defined by USGS. Our PR GIS team is trained by aerial photo interpretation experts at USGS and the State of Texas. Interpretation of aerial photos can be very subjective, therefore it is important to plan ahead and have well defined PR guidelines established. The GDM PR process is always being improved with new technologies and lessons learned during previous PR projects.