[GRASS-dev] new d.grid textcolor= option; nzgd2k datum offset versus WGS84

[Hamish]

Hi,

I added a new d.grid textcolor= option in 6.3-cvs.

Also I removed the lat/lon border skipping as it seems to work. (no new
code, just deleted the LL check+warning) If it proves problematic I think
we should keep the border but disable the tick marks.


outstanding wish: for a long time I've wanted GMT-style black/white bar
scale border for d.grid and ps.map.



I noiced something odd: using the NZTM projection (EPSG #2193),
"d.grid -g" and "d.grid -w" are approx 17.50 meters different.

  -g   Draw geographic grid (referenced to current ellipsoid)
  -w   Draw geographic grid (referenced to WGS84 ellipsoid)

EPSG file:
# NZGD2000 / New Zealand Transverse Mercator
<2193> +proj=tmerc +lat_0=0 +lon_0=173 +k=0.999600 +x_0=1600000 +y_0=10000000 +ellps=GRS80 +towgs84=0,0,0,0,0,0,0 +units=m +no_defs  <>


AFAIR, NZ Geoid Datum 2000 should be at most 10cm different in the vertical
versus WGS84 and virtually the same in the horizontal.

so why the difference?

datum:      nzgd2k
ellipsoid:  grs80
north:      4962100
south:      4961800
west:       1123250
east:       1123550

d.grid 0:00:05 -w
d.grid 0:00:05 -g

-PROJ_INFO-------------------------------------------------
name       : Transverse Mercator
datum      : nzgd2k
towgs84    : 0.000,0.000,0.000
proj       : tmerc
ellps      : grs80
a          : 6378137.0000000000
es         : 0.0066943800
f          : 298.2572221010
lat_0      : 0.0000000000
lon_0      : 173.0000000000
k_0        : 0.9996000000
x_0        : 1600000.0000000000
y_0        : 10000000.0000000000



??,
Hamish