[GRASSLIST:636] v.transform

[David Orme]

Hi,

I'm trying to import some eps vector graphics into GRASS 5.0 - I have 
converted the eps files to dig_ascii format files and they import into 
GRASS without problems. I now need to georeference the vectors, since 
the dimensions of the vector files are still in points from the 
graphics file.

I've tried using v.transform but I can't get a very good fit - does 
v.transform only provide first order transformations? If I knew the 
projection used to create the basemaps then I'd only need an affine 
transformation but, unfortunately, I don't have that information so I 
think I'm going to need to do a higher order transformation to get an 
acceptable fit. The maps are continent scale maps of Africa, so I'm not 
expecting miracles but I'd rather avoid having to save the graphics as 
tiffs and re-digitizing the polygon boundaries. I have a plan of the 
base map with a 10 degree graticule, which shows the central parallel 
at 0 and the central meridian at 20E but that is it.

Other suggestions welcome!

Thanks,
David

---------------------------------------
Dr. David Orme

Department of Biological Sciences
Imperial College London
Silwood Park Campus
Ascot, Berkshire SL5 7PY UK.

Tel: +44 (0)20 759 42358
Fax: +44 (0)20 759 42339
e-mail: d.orme at imperial.ac.uk