I am beginner of QGIS.

The purpose of using QGIS is making contour line and 3d visualization. I practice to make contour with DEM and it is not hard, but in my work, I have to treat contour line on paper maps.

I want to find line tracing tool or line detection tool to trace contour on scanned paper map. it is binary image and, unfortunately, contour line is not closed. Until now I make shapefile layer (line) and draw contour manually, of course, it is pretty time consuming.

I hope to find some method like, when I click some point, trace the line until meeting intersection or disconnection. then draw line manually, and restart line trace.

Do you know good method to do that?

I need your help.

  • I haven't done that this century, there used to be some really good tools available for that purpose but they're no longer available. Have a look at gis.stackexchange.com/questions/174707/… and see if that will get you at least some of the way to what you need. – Michael Stimson Nov 22 '17 at 1:08

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