[Gdal-dev] warping MODIS data with gdal
Markus Neteler
neteler at itc.it
Tue Nov 28 11:16:06 EST 2006
On Tue, Nov 28, 2006 at 09:12:53AM -0500, Stephen Hagen wrote:
> On Thu, 2006-11-23 at 17:49 +0300, Andrey Kiselev wrote:
> > Stephen,
> >
> > That is fixed now in CVS. Your dataset does not contain "HDFEOSVersion"
> > metadata record, which is used by GDAL to deduce whether we have HDF-EOS
> > or just plain HDF file. I added more logic to guess HDF-EOS variants.
> >
> > Best regards,
> > Andrey
>
>
> Thank you, Andrey. The HDF-EOS file (MOD09A1) and the projection
> information is now recognized by gdalinfo.
>
> Unfortunately, gdalwarp still fails to reproject this MODIS data
> accurately. I looked into Charles Wivell's suggestion that this might be
> related to confusion between geodetic and geocentric latitudes. I used
> the +geoc parameter in proj4, but I still have incorrectly reprojected
> data.
>
> I'm at a dead-end. If anyone figures out a fix to this, please post!
> Thanks for the responses.
Steve,
I didn't read the entire thread but maybe the information helps
that the MODIS Sphere differs from the standard sphere:
MODIS does not use the "Normal Sphere (r=6370997) but 6371007.181
I got this from:
http://edcdaac.usgs.gov/landdaac/tools/mrtswath/info/ReleaseNotes.pdf
I found some dirty trick to tell GDAL about it, see my script at:
http://mpa.itc.it/markus/useful/modis_hdf2erdas_ll_wgs84.sh
Please let me know if this works for you.
cheers,
markus
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