[GRASSLIST:2372] "Projection"-Choice for non-geographic analysis.

[Helmer Schack-Kirchner]

Dear GRASS-community,
we use GRASS for morphometric analysis and point statistics on 
microscopic images of soil cores.  GRASS is a powerful tool for this 
purpose, because it allows to analyze the spatial relationship of 
objects. However, our locations have extensions of maximum 4 cm, the 
resolution is 0.5 µm. We prefer 0/0 as the origin of our coordinate 
system.  Which "projection" and location parameters are the best choice 
for simple cartesic coordinate systems?
Best regards,
Helmer