[GRASSLIST:1514] How to measure plants?

[Slawomir K. Duda]

I try to measure plants (mosses, mainly Pleurozium schreberi) using GIS
software. I have scanned images of mosses and I want measure main lenght
and lenght of all branches with their position. I think this is similar
problem as with measure river lenght with lenghts and position of all
tributaries.
I'm new in GRASS and I've got lost in all commands. If anyone has idea how
to solve above problem I'll feel  very grateful for any information.

Slawomir K. Duda
Dept. of Ecology and Nature Prot.
Wroclaw Univ.