[GRASS5] How to patch vector maps?

[Markus Neteler]

Hi,

at time I try to understand how to intersect vector maps
topologically correct. What I did (using the Spearfish dataset,
latest version from the web site):

v.patch in=soils,fields out=soilsfarms.patch
# here v.support would print tons of warnings as expected
v.spag -si soilsfarms.patch
v.support soilsfarms.patch op=build

Still many warnings appear - is intersecting not possible
without getting attribute problems? Or am I on the wrong
roads?

Thanks,

 Markus