[GRASS-user] Datum <unknown> in v.in.ogr

[Hanlie Pretorius]

Hi,

I'm using QGIS to export shapefiles from WGS84 GCS to a local
projected coordinate system so that I can import the projected
shapefile into GRASS.

The PROJ4 definition that I use to export the shapefile (and that I
used to create the GRASS location) is:

+proj=tmerc +lat_0=0 +lon_0=29 +k=1 +x_0=0 +y_0=0 +ellps=WGS84
+units=m +no_defs


When I use v.in.ogr to get the shapfile into GRASS, I get the message:

'Datum <unknown> not recognised by GRASS and no parameters found
Projection of input dataset and current location appear to match'

Should I worry about the first part of the message?

The imported vector data does look a bit skew. It consists of
rectangles that should match raster DEM rectangles, but the outlines
now seem to be leaning a few degrees towards the left. Is this just a
result of the errors inherent in a projected coordinate system?

Thanks
Hanlie