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

[Brian Case]

Nikolaos

I have warped modis with swath2grid and mosaicked it with mapserver, I
have not seen that issue.

also you don't need to use a vrt to mosaic, this can be done with one
gdalwarp call.

gdalwarp file1 file2 file3 outfile


Brian

On Mon, 2011-07-25 at 17:20 -0700, Nikolaos Hatzopoulos wrote:
> It seems interesting I'll keep a note on this :)
> 
> The question is how you can build a VRT mosaic directly from MODIS hdf
> files, because
> the problem is that you have to mosaic first and after that to
> transform them to the
> EPSG:4326 projection. If you transform them first and mosaic them
> after you might have
> white lines.
> 
> --Nikos
> 
> 2011/7/25 Brian Case <rush at winkey.org>
>         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
>         >         gratis Handy-Flat!
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>         >
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