GPS to orthophoto discrepancy

Discussion created by KingsburyGID on Sep 7, 2012
Latest reply on Sep 11, 2012 by derklauer
Not sure if this is the correct forum for this question.

We are beginning to build a GIS for a smallish combined utility system (water sewer roads stormwater) with several hundred each ov valves, manholes, etc. We are collecting data with a Trimble GeoXH, but have noticed that even after differential correction, the results are a bit off (up to 3 feet) when laid over a recent georeferenced aerial.  We can't see everything on the aerial, or we would use just that to build from, but we are trying to get the best accuracy and precision for our points. So I am trying to figure out my best next step: if I move the points to the apparent correct locations on the map, I get a warning about losing the GPS data, and it asks about rebuilding, which puts the point back where it started. I guess I could try a hybrid approach and not GPS the points I can see, but that could get confusing. Any ideas for a workflow for this?

Eric Johnson