[GRASS5] Re: g.region -l

Hamish hamish_nospam at yahoo.com
Thu Mar 4 20:17:58 EST 2004

> > > BTW: Maybe we should modify '-l' of g.region to work on WGS84
> > > (like d.where)? Or just advertise that the current datum is used?
> > > I am not sure what's preferred.

> > Better to keep things consistent unless there's a good reason for
> > changing


> > (there was for d.where; it used the old coorcnv library and part of
> > the functionality worked only in UTM locations).
> So that's a vote to change g.region. I tend to agree, because a
> reliable WGS84 output is better than a sort of undefined LatLong
> output with current datum/ellipsoid. 
> Other opinions?

d.where has

  -d   Output lat/long in decimal degree
  -l   Output lat/long referenced to current ellipsoid
  -w   Output lat/long referenced to WGS84 ellipsoid using datum
        transformation parameters defined in current location if available
  note descriptions aren't very clear and could probably be improved..
    -d is independent of datum/ellps choice;
    -l should change to ellps/datum;
    -w wording is awkward

   the program will prompt you if you try and mix them improperly though.

g.region should match, I think all that means is adding a -w flag to 
get a WGS84 version of -l. (I think the default action should be to use
the current ellps/datum)


ps - 
GRASS53> d.where -w

                                                   WGS84 Co-ordinates
             EAST:             NORTH:               LON:               LAT:
pj_transform() failed
cause: failed to load NAD27-83 correction file
ERROR: Error in pj_do_proj()

GRASS53> g.projinfo
name:    New Zealand Map Grid
datum:   nzgd49
nadgrids:        nzgd2kgrid0005.gsb
proj:    nzmg
ellps:   international
a:       6378388.0000000000
es:      0.0067226700
f:       297.0000000000
lat_0:   -41.0000000000
lon_0:   173.0000000000
x_0:     2510000.0000000000
y_0:     6023150.0000000000

I thought that used to work.. hmph. same old NTv2 PROJ bug?
If I change back to the 7-param transform it works.

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