I'm trying to dissolve a polyline feature class so that spatially intersecting features become a single feature. When I run the Dissolve tool, setting
Create multipart features and
Unsplit lines both to false, I get unexpected results. In the example below, two line features I'd hoped to dissolve into one became three line features:
Is there a way to dissolve a line feature class so that any touching features dissolve into one?
I think your problem is that you need to leave "Create Multipart Features" set to True. The line you're describing is a multi-part line. By setting "Create Multipart Features" to false, you're telling the GIS to split those lines into two features.
All three or four way intersections or non-intersecting crossing lines that dissolve are by definition going to form multi-part lines, since single part lines by definition can only have two end vertices and only two segments maximum can meet at any connecting vertex.
The way to do this is as follows:
You will end up with what you are looking. Every lines that touches another line at any crossing or intersection of any kind will have merged into a single polyline feature. These polyline features will nonetheless be a multi-part line feature anytime a line crossing or 3-way or greater intersection exists.
I think you will get what you want if you set both Create multipart features and Unsplit lines to TRUE (on). That unsplits contiguous lines but does not create discontiguous multipart features.