[GRASS-dev] r.stats area question

[Glynn Clements]

Eric Goddard wrote:

> My coordinate system is in U.S. Feet (I know, I know...we're still in
> the dark ages). The numbers do appear to be meters, but I just wanted
> to confirm that the output isn't in feet because of the "assuming the
> map's coordinate system is in meters" part.

Areas are always in square metres, provided that sufficient
information is available to perform conversion.

For lat-lon locations, the conversion is based upon the ellipsoid
parameters and the cell's latitude.

For projected locations, the area per cell is a constant based upon
the location's declared units (i.e. the meters= value in the ouput of
"g.proj -g").

This has been the case since at least the oldest version in the
repository (~14 years ago).

AFAICT, the only situation where you could get output in "map units"
is for an X-Y location or a projected location which lacks a
PROJ_UNITS file.

-- 
Glynn Clements <glynn at gclements.plus.com>