[postgis-users] WGS84 to meters

[Willy-Bas Loos]

> >A global equal-area projection would
> >be better, in that you can use the same parameters regardless of where
> >on the globe you're working.  I have a similar application, and use
> >Cylindrical Equal Area.  I use something like (with an old version of
> >PostGIS -- I think the function names all start with ST_ now):
> >
> >select sum(area(transform(glacier_polys,32767)))  FROM glacier_polygons
> ...
>
>
cool,thanks.
distance sphere is also working great.
I see that there is also an ST_length_spheroidI(nice, though .._sphere is
missing).

I know how to calculate distances now, but for area calculation or buffering
i still have to transform to a different coordinate system.
Using a single coordinate system for the whole globe is already a great
improvement, but i still have to be cautious to use the right transformation
for the calculation that i want to do.

Wouldn't it be great if GEOS (i mean postgis really) could do calculations
for WGS84 (which would store anything "lossless") in meters?
We can already compute distances in meters, so why can't we do all
calculations (area, buffer) in WGS84 ??

As for buffers, it should be possible to make a buffer_sphere and a
buffer_spheroid, because distance calculations is all it takes (afaik).
If someone would invent a way to create an "area_sphere" and
"area_spheroid", i would see no more need to store geometries in anything
else than WGS84.

Any thoughts on that?

Cheers,

WBL
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