[GRASS-user] Re: visualising high latitude regions

[Hamish]

Wouter wrote:
> is there a way in GRASS to draw latlong projection data with a
> non-straight coordinate grid? Something like this:
>  <http://www.lib.utexas.edu/maps/americas/chile.gif>
>
> Particularly for high latitudes such as Patagonia, a straight grid
> gives a lot of distortion.
....
> Answer to my own question:
>
> - have your data in UTM
> - make a grid in a latlong location with v.mkgrid
> - reproject the grid to your UTM location with v.proj
> - visualise the grid over your data of interest
> - add labels with the latlong coordinates

which is nice if you want to output a shapefile to use as an overlay
with e.g. QGIS, but there is a much much easier way...

use 'd.grid -g size=0:30' or 'd.grid -w size=5' to draw eg 30min or 5deg
lat/lon grid over your current map projection display.
d.grid has a number of nice options.

also in ps.map there is the "geogrid" command which does something similar.


Brent wrote:
> Yep, GRASS can do it that way, I suggest you look at GMT
> (http://gmt.soest.hawaii.edu) for quality map production & cartography...

& ps.map :)
 
> OGR now supports GMT vector  (multiline) output, so it is easy to
> convert data to GMT format for plotting.

OGR tip added to the GRASS/GMT wiki page:
  http://grass.osgeo.org/wiki/GRASS_and_GMT

(that page, and the [r|v].[in|out].gmt scripts really need a cleanup)


Hamish