[GRASS-user] Correct import of a global grid (0E to 360E) to GRASS (-180W to 180E).

[Hamish]

Michael wrote:
> Which way does it get flipped? 
>
> Most NetCDF files will import via r.in.gdal correctly, but they
> are displayed as (from L->R) as 0->180E/180W->0. This is the way
> that most climate model files are created and then stored.

note I've had some data in the past which either had bad meta-
data embedded in it or GDAL was reading wrong. GRASS itself should
deal with 0-360 longitudes just fine for raster maps. But if the
import goes wrong for whatever reason it is easy to fix by
resetting the bounds with r.region.

> This presents some problems in displaying vector overlays (I've
> reported this to the bug tracker).

note the vector lib and modules not nearly as robust wrt 180
longitude as the raster lib & modules are. mostly a function of
age I guess.

> There has been a problem in NetCDF files importing upside down.
> This fixed in the current version of GDAL AFAICT.

Right, you can work around that one with the r.flip addon module.


Hamish