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.