I have 30 years experience as a licensed surveyor in California but I'm just beginning to learn GIS. I have a client that wants me to locate the County Line. Trouble is, the legal definition of the County Line is the drainage divide line running along a ridge line. This isn't much of an issue where the ridge line is well defined, but does become a problem in the flatter saddle areas.
My research turned up papers on "Watershed Algorithms" and it appears to me to be the answer for locating--as accurately as possible--such a drainage divide line. At first I thought that I could handle this myself, once I found a suitable software routine. But now I am assuming that it would behoove me to hire a GIS sub-consultant with experience in using watershed algorithms.
My client has already used aerial lidar to develop a DEM of the area in question. Can anyone point me to someone who can take this data and crunch out a divide line for me?
Hi Lee, I got some pretty good results using Manifold GIS with its surface tools extension. But, imho, the best results for this kind of analysis would be RiverTools (www.rivertools.com). Rivix also offer consultancy services and I've always found them to be very helpful. Dave