[GRASSLIST:5459] geogrid in ps.map

[Ian MacMillan]

Hi all, I am using grass5.7 on osx (May 2004 or so) and I am trying to 
make a world mercator map using ps.map.  I would like to add a geogrid, 
however the output only gives latitudinal lines, no longitudes.  No 
errors were returned.  The command I gave was

ps.map input=- output=test.eps -e
geogrid 30 d
color black
numbers 1
end
end

g.region -p yields

projection: 99 (Mercator)
zone:       0
datum:      ** unknown (default: WGS84) **
ellipsoid:  wgs84
north:      11714654.84
south:      -11714654.84
west:       -20037508.34
east:       20037508.34
nsres:      3697.80771465
ewres:      3710.64969259
rows:       6336
cols:       10800


Alternatively, I have also tried to import (using v.proj) a worldwide 
vector grid with 30 degree spacing, however every attempt to import 
yields in errors such as (using grass 5.3):

Input Projection Parameters: +proj=latlong +a=6378137 
+es=0.006694379990141316 +towgs84=0.000,0.000,0.000

Output Projection Parameters: +proj=merc +lat_ts=0.0000000000 
+lon_0=180.0000000000 +k_0=1.0000000000 +a=6378137 
+es=0.006694379990141316

Creating dig file...
pj_transform() failed
cause: latitude or longitude exceeded limits
Error in pj_do_proj

OR (using 5.7)

v.proj input=grid30 location=latlong_wgs84

Input Projection Parameters: +proj=latlong +a=6378137 +rf=298.257223563 
+no_defs +towgs84=0.000,0.000,0.000
Input Unit Factor: 1

Output Projection Parameters: +proj=merc +lat_ts=0.0000000000 
+lon_0=180.0000000000 +k_0=1.0000000000 +a=6378137 +rf=298.257223563 
+no_defs
Output Unit Factor: 1

Creating vector file...
Building topology ...
Registering lines:

At this point v.proj stops running.  Trying to display the vector with 
yields:

GRASS 5.7.0:~ > d.vect grid30
WARNING: coor files of vector 'grid30 at ianmacmillan' is larger than it
          should be (14312 bytes excess).
WARNING: Cannot display areas, topology not available

I think there is a problem with worldwide mercator projections, but I 
can't figure what it is.  Displaying other worldwide data (I can't 
remember how I got it into this location in the first place) shows that 
the region is appropriate for a world map.  It is hard to tell for sure 
though since units are measured in meters.

Any ideas?

Thanks,
Ian