On Monday 06 July 2009, Frank Warmerdam wrote: > Dylan Beaudette wrote: > > Hi, > > > > > > Does anyone on the list know how to either convert or extract data as > > delivered in the "free data" section [1] of the AVIRIS home page? I > > have tried working with the "radiance" data, which when uncompressed > > comes with several ".img" files-- however my copy of GDAL (1.7) does not > > know what to make of it. > > Dylan, > > I downloaded the cuprite radiance data and the readme says: > > > *.img CALIBRATED AVIRIS RADIANCE (IMAGE) DATA > > Contents: AVIRIS calibrated radiance multipled by the gain and stored as > 16-bit integers. > File type: BINARY 16-bit signed integer IEEE. > Units: gain times (microwatts per centimeter_squared per nanometer per > steradian). > Format: Band interleaved by pixel (channel, sample, line) with > dimensions (224, 614, 512). The last scene may be less than 512. To > calculate the number of lines divide the file size by 275,072 bytes per > line. > > So it is a normal bigendian signed 16bit integer pixel interleaved dataset > with a width of 614, a length of 512 and 224 bands. > > Based on the VRT tutorial at http://www.gdal.org/gdal_vrttut.html I wrote > a .vrt file that allows access to the first band. > > <VRTDataset rasterXSize="614" rasterYSize="512"> > <VRTRasterBand dataType="Int16" band="1" subClass="VRTRawRasterBand"> > <SourceFilename > relativetoVRT="1">f970619t01p02_r02_sc01.c.img</SourceFilename> > <ImageOffset>0</ImageOffset> > <PixelOffset>448</PixelOffset> > <LineOffset>275072</LineOffset> > <ByteOrder>MSB</ByteOrder> > </VRTRasterBand> > </VRTDataset> > > gdalinfo -mm sc01.vrt > Driver: VRT/Virtual Raster > Files: sc01.vrt > Size is 614, 512 > Coordinate System is `' > Corner Coordinates: > Upper Left ( 0.0, 0.0) > Lower Left ( 0.0, 512.0) > Upper Right ( 614.0, 0.0) > Lower Right ( 614.0, 512.0) > Center ( 307.0, 256.0) > Band 1 Block=614x1 Type=Int16, ColorInterp=Undefined > Computed Min/Max=686.000,1381.000 > > To support more bands just add additional copies of the VRTRasterBand > section changing the band#, and adding two to the ImageOffset each time. > eg. > > <VRTDataset rasterXSize="614" rasterYSize="512"> > <VRTRasterBand dataType="Int16" band="1" subClass="VRTRawRasterBand"> > <SourceFilename > relativetoVRT="1">f970619t01p02_r02_sc01.c.img</SourceFilename> > <ImageOffset>0</ImageOffset> > <PixelOffset>448</PixelOffset> > <LineOffset>275072</LineOffset> > <ByteOrder>MSB</ByteOrder> > </VRTRasterBand> > <VRTRasterBand dataType="Int16" band="2" subClass="VRTRawRasterBand"> > <SourceFilename > relativetoVRT="1">f970619t01p02_r02_sc01.c.img</SourceFilename> > <ImageOffset>2</ImageOffset> > <PixelOffset>448</PixelOffset> > <LineOffset>275072</LineOffset> > <ByteOrder>MSB</ByteOrder> > </VRTRasterBand> > </VRTDataset> > > You might want to write a small script to create this for 224 bands. > Note the SourceFilename element - update this for other cubes. > > The same approach should work for the reflectance cubes (.rfl) if you > are interested in them. > > Best regards,
Thanks Frank. This works well. Now I need to figure out how to apply the geo-rectification / distortion corrections from the .nav files... Some ideas here: ftp://popo.jpl.nasa.gov/pub/docs/workshops/99_docs/7.pdf Cheers, Dylan -- Dylan Beaudette Soil Resource Laboratory http://casoilresource.lawr.ucdavis.edu/ University of California at Davis 530.754.7341 _______________________________________________ gdal-dev mailing list gdal-dev@lists.osgeo.org http://lists.osgeo.org/mailman/listinfo/gdal-dev
