[Taxacom] Geodetic datums do matter

[Erast Parmasto]

M, 23 March 19:46, Doug Yanega wrote:
>
> It matters, but how MUCH it matters (the actual practical
> implications) will DEPEND ON CONTEXT.
>
    How much it depends is depending on time factor sometimes. In Estonia,
we have on collecting labels the data of some very rare fungal species
with coordinates determined using older types of GPS up to ten years
ago already. Now these species are protected by law in this country,
and it is really important where a locality is actually situated. In a
small forest of one owner of the land plot, or in a neighbouring
forest owned by another man. Using easily available maps (aerophotos),
sometimes an old locality of a wood-rotting old-growth forest fungus
seems to be in the middle of a small lake. When the specimen was
collected, the exact coordinates were of less importance; today we
have another context, and it matters much more.
     When studying distribution of protected fungal species last year in
Estonia, we got the coordinates of some localities twice: first,
using small portable GPS (during some 5 minutes; no GPS station set
nearby); second, getting the coordinates (using MapInfo or other
programs) of the locality from the (aerophoto)map 1 : 1000 where
boundaries of the real properties or forest subcompartments are added
as an additional layer. (However, the difference between the two
datasets was remarkable sometimes.) Alas! this is not always
possible, and never for old localities.
     In other words: exactness of coordinates may be more important in
future than today.
*****
Erast Parmasto
Institute of Agricultural and Environmental Sciences
181 Riia St., 51014 Tartu, Estonia
eparmasto at yahoo.com
erast.parmasto at ut.ee
erast.parmasto at emu.ee