[GRASS-user] Understanding Regions and Windows

[Glynn Clements]

Rich Shepard wrote:

>    Starting grass64 from /usr4/grassbase/Oregon I request a listing of the
> region's boundaries and see this:
> 
> 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
> 
>    I've no idea where these values are to be found because in
> /usr4/grassbase/Oregon/rbs/WIND I see this:
> 
> [rshepard at salmo /usr4/grassbase/Oregon]$ less rbs/WIND 
> proj:       99
> zone:       0
> north:      46.15916
> south:      41.933088
> east:       -116.644278
> west:       -124.719106
> cols:       1
> rows:       1
> e-w resol:  8.074828
> n-s resol:  4.226072
> top:        1
> bottom:     0
> cols3:      8
> rows3:      4
> depths:     1
> e-w resol3: 1.0093535
> n-s resol3: 1.056518
> t-b resol:  1
> 
>   Even this is incorrect from the definition of the region and projection
> using the wxPython UI, because the e-w resolution and the n-s resolution are
> both supposed to be in International Feet and were entered as 32.8286760.

The "proj: 99" indicates a cartographic coordinate system, but the
region boundaries seem more appropriate for lat/lon.

>    I'd like to understand where the incorrect corners are found, why the
> region listing does not match the window in the rbs mapset (which matches
> the DEFAULT_WIND and WIND in the PERMANENT mapset, and how to fix this up.

What are the contents of PERMANENT/DEFAULT_WIND and PERMANENT/WIND?

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