[GRASS-user] g.region Options Yield Different Values

[Glynn Clements]

Rich Shepard wrote:

>    Please explain to me why g.region -l shows region corners outside the
> coordinate values shown by g.region -p. Makes no sense to me when they are
> both run from the same location/mapset:
> 
> GRASS 6.4.0svn (Oregon):/usr4/grassbase/Oregon > g.region -p
> projection: 99 (Lambert Conformal Conic)
> zone:       0
> datum:      nad83
> ellipsoid:  grs80
> north:      46.15916
> south:      41.933088
> west:       -124.719106
> east:       -116.644278
> nsres:      4.226072
> ewres:      8.074828
> rows:       1
> cols:       1
> cells:      1
> GRASS 6.4.0svn (Oregon):/usr4/grassbase/Oregon > g.region -l
> north-west corner: long: 125:18:06.67543W lat: 41:38:42.416382N
> north-east corner: long: 125:18:06.327366W lat: 41:38:42.431669N
> south-east corner: long: 125:18:06.3167W lat: 41:38:42.29503N
> south-west corner: long: 125:18:06.664764W lat: 41:38:42.279743N
> center longitude:  125:18:06.496065W
> center latitude:   41:38:42.355706N
> rows:              1
> cols:              1

Because g.region -p shows the cartographic coordinates in metres/feet
in the specified coordinate system (LCC, with the origin at
approximately 41:38:42N, 125:18:06W), while g.region -l shows the
coordinates converted to lat/lon.

The reason is almost certainly that lat/lon coordinates were used
where cartographic coordinates were required.

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