Create points where vector lines from two maps intersect

Question

I have two vector maps, one showing a single polygon (land), and the other multiple vector lines (rivers. I'm trying to create a map of points that indicates where the river vector lines intersect geographically with the land edge. I need a points map of the river mouths as I want to create a stream order map. Using v.select simply creates a new vector map where the overlaps have occurred, it doesn't create a points map. This is using GRASS 7.8.6

v.select ainput=rivers binput=land output=river_mouths operator=crosses

score 0 · Answer 1 · answered May 10 '22 at 09:21

OK, I think I've come up with a solution. It works for me as all my rivers were originally digitised in the same direction. Some of my rivers 'overshoot' the land (they extent several km into the see) and this error needs correcting:

v.overlay ainput=rivers binput=land output=new_rivers operator=and

Having corrected that, I can then identify the correct start of the river

v.to.points input=new_rivers output=river_mouths use=start

Create points where vector lines from two maps intersect

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