[GRASS-user] creating vector grids (especially associated with projections)

Hamish hamish_b at yahoo.com
Wed Feb 16 07:35:10 EST 2011

Patrice wrote:
> But for other grids, like a non regular lon lat grid (more precise in
> the middle)

nested or non-linear?

> or for a lambert conformal 'natural' grid (which are the examples
> I have) or any other grid that could arise, is there a simple way to do
> a vector corresponding with that grid?

try the v.mkgrid module. then use v.proj to pull it into the other

in LCC or some other projection you can run d.grid, and "d.grid -w" to
get both local grid and lat/lon grid over the top of each other.

neither v.mkgrid or d.grid are very happy with 180 longitude, but using
0-360 instead of -180 to +180 can help there. (?)

> If not, are there some code somewhere that helps doing geometric vectors,
> like grids (but one could also imagine doing circles and so on)

see the GRASS raster screenshots page for polar stereographic projection
with a lat/lon grid made by v.mkgrid reprojected into the local projection.
(making circles around the poles)

> Something like a high level API to do vector geometries, and not
> something where you have to enter every coordinate and curve
> informations?

create SVG in Inkscape, save as DXF, import DXF into GRASS.

> Also are you aware of people interested in such developments, are there
> library of vector code/features/scripting or similar in the open source 
> GIS community?

for really sophisticated mesh grids have a look at Pavel Sakov's tools:
and the front-end to that Octant:

good luck,


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