Hi, I'm trying to make a model of a contour map. I've imported a dxf of the contour lines from Illustrator, and that resides as a sketch in my part. My current method involves selecting all the curves of a given elevation, and converting them to a new sketch, then closing it off and extruding on top of the previous extrude. This is tedious to select all the curves, especially since some of them are very small, and I have to zoom in to select. Is there a shortcut to have Solidworks select all the curves that are touching eachother and share end points?

Alternatively, if anyone has a better idea of how I can go about automating this process, that would be awesome, I just can't think of a better way, myself. I could import individual dxf files for each elevation, if that would help an automation process somehow.