The GDAL data model does specifically call out the top-left corner of the top-left pixel as the origin. Not sure if that's helpful, but I remember having to look this up before.
http://www.gdal.org/gdal_datamodel.html On Mon, May 18, 2015 at 8:31 AM, Yuta Sato <[email protected]> wrote: > Dear all: > > Thanks for sharing your ideas and experiences. > > As I mentioned in my question, it seems that MRT result is shifting right > while the GDAL warp result is correct. Do you agree? > > The exact upper left corner of the original HDF-EOS file is exactly as the > GDAL warpped result. > > The HDF file uses top left corner of top left pixel, while the MRT seems > to use central of top left pixel (MRT userguide page 10 under corner > coordinates section), am I right? > > > https://lpdaac.usgs.gov/sites/default/files/public/mrt41_usermanual_032811.pdf > > If I am right, fortunately the GDAL would win! > > > > > > On Mon, May 18, 2015 at 11:24 PM, Markus Neteler <[email protected]> > wrote: > >> On Sun, May 17, 2015 at 1:32 PM, Even Rouault >> <[email protected]> wrote: >> > Le dimanche 17 mai 2015 12:54:44, Markus Neteler a écrit : >> >> On Sun, May 17, 2015 at 6:44 AM, Yuta Sato <[email protected]> >> wrote: >> >> > Dear GDAL and Proj Developers and Users: >> >> > >> >> > I am really frustrated when the MODIS HDF file converted into GeoTiff >> >> > with GCS projection never match with the same MODIS file converted >> from >> >> > MODIS Reprojection tool. >> >> >> >> We had this issue in the past, too, for our "EuroLST" project >> >> (gap-filling of all LST maps for Europe, see >> http://gis.cri.fmach.it/eurolst/). >> >> Solved since then, see below. >> >> ... >> >> >> >> > Do you have any idea on which is more precise: gdalwarp or MRT? Or >> there >> >> > is any way in gdalwarp to get the same image as MRT gives? >> >> An addition: >> >> For our EuroLST project we use EU LAEA as target projection. In our >> tests (we made a lot) the MRT results came out shifted by 0.5 -1.0 >> pixel since MRT does not support a datum or ellipsoid for LAEA (LA in >> MRT), instead it supports only a sphere when reprojecting from MODIS >> sinusoidal. >> >> Using recent GDAL, gdalwarp does the reprojection from MODIS >> sinusoidal to EU LAEA correctly. >> >> >> You may take a look at >> >> http://pymodis.fem-environment.eu/ >> >> >> >> pyModis >= 1.0 comes with fast GDAL support (way faster than MRT). >> >> >> >> The details of the gdalwarp usage you find in the source code here: >> >> >> https://github.com/lucadelu/pyModis/blob/master/pymodis/convertmodis_gdal.py >> > >> > Markus, >> > >> > for the sake of my curiosity, could you explain what specific stuff it >> does >> > compared to gdalwarp ? I quickly skimmed through the file and only saw >> regular >> > use of the GDAL warping API. But perhaps I missed something. >> >> pyMODIS is a set of scripts and a library to perform the download of >> large numbers of MODIS HDF/XML files (think cronjob), it creates a >> mosaic of several tiles, it extracts specific information from >> bit-encoded MODIS quality assessment layers of different product types >> etc. >> >> Essentially a ready to use product which happily uses GDAL as a backend. >> >> Markus >> >> -- >> http://courses.neteler.org >> http://gis.cri.fmach.it/neteler/ >> http://grass.osgeo.org >> _______________________________________________ >> gdal-dev mailing list >> [email protected] >> http://lists.osgeo.org/mailman/listinfo/gdal-dev >> > > > _______________________________________________ > gdal-dev mailing list > [email protected] > http://lists.osgeo.org/mailman/listinfo/gdal-dev >
_______________________________________________ gdal-dev mailing list [email protected] http://lists.osgeo.org/mailman/listinfo/gdal-dev
