[Gdal-dev] gdalwarp UTM->TM

[Frank Warmerdam]

Jun Wada wrote:

> Hello:
> I have one problem about gdalwarp "UTM->TM".
> Please let me know.
> I tried to "UTM->TM" by using gdalwarp.
> It made a TM-Image file and I checked it by using gdalinfo.
> "Corner Coordinate"is OK but "DATUM" is "unknown" and also "SPHEROID" is
> "unnamed".
> I don't know why ?
> When I executed the gdalwarp, I specified Tokyo in "DATUM" and bessel in
> "SPHEROID" but...
...
> gdalwarp command:
> gdalwarptest -et 1.0 -rc -order 3 -t_srs "+proj=tmerc +zone=9 +ellps=bessel
> +towgs84=-147.54,507.26,680.47,0,0,0 +k=0.9999 +units=m +to_meter=1.0
> +lat_0=36
> +lon_0=139.833333333 +datum=Tokyo" po_utm54_0-2.tif trans01.tif

Jun Wada,

There is no such datum predefined to PROJ.4 as "+datum=Tokyo", so this
presumably had no effect.  At the very least, the level of code that
would be responsible for parsing things for writing the TIFF file wouldn't
know the Tokyo datum even if you had hacked it into PROJ.

However, I see the output file did have the right parameters for the
Bessel ellipsoid even though it wasn't recognised by name.  So the image
results should be OK even if the GeoTIFF metadata is a bit dodgy.

Best regards,
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