Watershed Analysis - Interference from Road
Hi, I'm new to the forum and have only been using Global Mapper for a few months. I'm using GM version 18.2 (I have also tried it on v17.2).
I'm trying to do a watershed analysis of a mountainous area. Both intuitively and using the legend for the atlas shader, I know that one large river at the base of the mountains is the low point in the topography. However, when I run the analysis, the watershed area features end at a small highway that lies between the slopes and the river. New watershed features begin on the other side of the highway. This seems incorrect to me. I've tried creating a line feature along the river and checking "create watershed areas showing drainage to selected lines", but nothing has fixed the problem.
Any suggestions would be helpful . Thanks!