>I see a potential problem with this. When you want to place a
>circle or triangle over a particular habitat, where will you
>choose to place the center of the circle ?
This problem can be addressed in a very pragmatic (yet scientifically
correct) way. Do you perhaps know the "Atlas Florae Europaeae" (AFE)? In
this work, location data are given for any and all vascular plant species
(and some subspp. as well, including also some most rare local endemics:
one point/planet) growing in the "Flora Europaea" region (Fernando: this is
*really* a tough job!). The distribution points (mostly symbolized by
circles) are snapping to a grid (quite similar to the one proposed by
Rick). So the information which can be retrieved is that within an area of
-say- 100 sq. km, at least one site is known. This is 1. accurate enough
for biogeographical studies and an area outline and 2. safe enough to
prevent the ignorant (i.e. too dumb to find more specific literature)
unscrupulous vandal from pinpointing the last individual with the aid of
the maps.
More precise information is available to the editors of AFE, and still (I
think, at least) nobody has accused them of either opening the gates for
the unscrupulous, or hiding indispensable information.
I for one (I know I am not really alone!) find the AFE a most useful tool
(impatiently waiting for the next vols. to appear).
Kind regards
Jan