[gdal-dev] Modis L1B SWATH: georef problem hdf to geotiff

[Brian Case]

anna, Nikolaos,

after much experimentation I found something that seems to work.

gdalwarp --config GEOL_AS_GCPS FULL \
         -tps -geoloc -t_srs EPSG:4326 \
         -te -119.88004906118 13.5092548294379 \
         -92.6036641645677 34.7070050511582 \
HDF4_EOS:EOS_SWATH:"MOD02HKM.A2011169.1750.005.NRT.hdf":MODIS_SWATH_Type_L1B:EV_500_RefSB \ MOD02HKM.A2011169.1750.005.NRT.tif

note i tried to escape the newlines to make it easy to read but the
email may mess that up.

there is about 2.7 million gcp's in a normal 5min modis swath file, by
default gdal only reads every 10th row and column of gcp's this is not
enough to handle the bowtie effect.


Brian

On Tue, 2011-01-18 at 16:33 -0800, Nikolaos Hatzopoulos wrote:
> You are right, I notice that there isn't any difference from the
> band_1.tiff and band_1_warp.tiff
> 
> --Nikos Hatzopoulos
> 
> On Mon, Jan 17, 2011 at 8:15 AM, anna auge <annaauge at web.de> wrote:
>         Hi all,
>         
>         I am trying to convert modis level 1B data (type SWATH) to
>         geotiff following these steps.
>         
>         1) Examining the HDF
>         gdalinfo d:\modis\1b
>         \MOD021KM.A2011008.0850.005.2011008195744.hdf
>         gdalinfo HDF4_EOS:EOS_SWATH:"d:\modis\1b
>         \MOD021KM.A2011008.0850.005.2011008195744.hdf":MODIS_SWATH_Type_L1B:EV_1KM_RefSB
>         2) Extracting the 1. band of the subdataset
>         MODIS_SWATH_Type_L1B:EV_1KM_RefSB
>         gdal_translate -of GTiff -b 1 HDF4_EOS:EOS_SWATH:"d:\modis\1b
>         \MOD021KM.A2011008.0850.005.2011008195744.hdf":MODIS_SWATH_Type_L1B:EV_1KM_RefSB d:\modis\1b\band_1.tiff
>         4) Warping the image to WGS84
>         gdalwarp -t_srs EPSG:4326 d:\modis\1b\band_1.tiff d:\modis\1b
>         \band_1_warp.tiff
>         
>         The example dataset, which i am using, can be downloaded here
>         ftp://ladsftp.nascom.nasa.gov/allData/5/MOD021KM/2011/008//MOD021KM.A2011008.0850.005.2011008195744.hdf
>         
>         And now to my problem: I get always an certain shift
>         (http://www.flickr.com/photos/54033867@N00/5363471425/in/photostream/), which is avoided if i am using the "Georeference MODIS" option in ENVI (http://www.flickr.com/photos/54033867@N00/5364083966/in/photostream/).
>         I also tried a few workarounds, f.g.
>         http://thread.gmane.org/gmane.comp.gis.gdal.devel/10482, but
>         nothing worked properly.
>         As far as I understand gdal supports Modis L1B SWATH, so what
>         I am doing wrong? Any help is appreciated.
>         
>         Regards Anna
>         
>         P.S. I am using FWTools 2.4.7 on Windows
>           
>         
>         
>         WEB.DE DSL Doppel-Flat ab 19,99 ¤/mtl.! Jetzt mit    
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