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

Brian Case rush at winkey.org
Tue Jul 26 13:40:17 EDT 2011


Nikolaos,

I believe the only limitations will be ones imposed by the shell/os on
the number of arguments that can be passed to an app (2^15?), and the
cpu and memory resources available.

Brian

On Tue, 2011-07-26 at 09:38 -0700, Nikolaos Hatzopoulos wrote:
> cool!
> 
> does it works with 150 files?
> 
> --Nikos
> 
> On Tue, Jul 26, 2011 at 9:17 AM, Brian Case <rush at winkey.org> wrote:
>         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!
>         >         >
>         http://produkte.web.de/go/DSL_Doppel_Flatrate/2
>         >         >
>         >         >
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