So I need to extract the steiner tree along a line network connecting a set of points. The one part I don't quite get is what to add for the required Category values parameter.
I initially thought that it was the range of category values for the nodes so I entered 1 - 340. However I received the following error when I tried to run the algorithm:
Number of terminals: 0 ERROR: Not enough terminals (< 2)
I'm quite new to using GIS and GRASS in particular. Any help would be great.