> PostGIS, geometry columns, and UTM.. I'm not sure where they are wrt
> adding KNN support, but it's something they've been anxious to have for
> a while, so I expect support will come quickly.
I've looked into this a little more.
One approach seems to be to project the lat/long pairs on to a flat
plane using the Albers projection (which would be a one-time
calculation), and then the current KNN point/distance calculations could
be used.
Here's a Perl module that references the Albers projection (although
it's not yet clear to me how to use it):
http://search.cpan.org/dist/PDL/
And a Wikipedia page on various calculation possibilities:
http://en.wikipedia.org/wiki/Geographical_distance#Flat-surface_formulae
Further suggestions welcome.
Thanks,
Mark
