[gdal-dev] Clarke 1880 Cape Datum for gdalwarp

Zoltan Szecsei zoltans at geograph.co.za
Wed Jul 25 06:47:23 PDT 2012


Hi,
Not sure if this should go to proj list, but I would like to transform 
about 14 jpg orthos (already in a vrt)
from Clarke 1880 Cape Datum, Lo33 to WGS84 Hartebeeshoek94 datum UTM 43S

The jpw file has:
0.0500000000000000030
0.0
0.0
-0.0500000000000000030
-50999.974999999999
-2872000.0249999999
so you'll probably notice that it is not the usual Gauss Conformal 
projection, as that would be +ve South and West for this area.

I'm having a bit of trouble finding the correct s_srs and t_srs values 
for gdalwarp.
I'm presuming that by inputting a vrt to gdalwarp, I will get 1 nice big 
ortho (instead of the 14 jpeg in the vrt), and I can then cut that up 
into 1Km squares on the new projection.

Once the orthos are done I will be needing to transform (as above) a 3D 
DGN file (yep, I'll re-write it as v7) and an ASCII DEM file as well. 
Typical DEM values are:
-50400.000,-2872481.000,-2.74
-50399.000,-2872481.000,-2.84


I'd be grateful for some help specifying the input and output CRS's

Thanks & regards,
Zoltan


-- 

===========================================
Zoltan Szecsei PrGISc [PGP0031]
Geograph (Pty) Ltd.
P.O. Box 7, Muizenberg 7950, South Africa.

65 Main Road, Muizenberg 7945
Western Cape, South Africa.

34° 6'16.35"S 18°28'5.62"E

Tel: +27-21-7884897  Mobile: +27-83-6004028
Fax: +27-86-6115323     www.geograph.co.za
===========================================



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