I have a large set of collected GPS points that I'm pulling into Arcgis from SQL and creating an xy event layer to then map them. The fields for the points are as follows: recorded, lat, long, altitude, speed, hAccuracy, vAccuracy.
Overall the points are fairly accurate, but of course there are a few cases where the accuracy is off by quite a bit. I have worked with differential correction before, but it was with the same software/hardware (Trimble/Pathfinder) used to collect the data.
Is it possible to correct the points after I have created a shapefile? If not, is it possible to correct with the Pathfinder software them before I bring them into GIS? I also realize that if in fact I can correct them I will have to pull use multiple base files as the GPS points collected are over multiple dates.
Any ideas or help is greatly appreciated!
Best Answer
If you have the ssf file that the points were in then you should be able to run them through the Pathfinder software for the correction. I've generally found that the differential correction by pathfinder was never more than a few inches. So the data collector may have been off instead of the fact that the satellites broadcast was mis-interpreted. If anyone has seen different I'd be happy to know.
To correct just the shapefiles (or the points themselves) I think you would need to know which satellites were broadcasting the positions and at exaclty what time. And possibly how many points were collected for each shot and how they averaged. Whew!
That would be very cool if someone has some insight on that.