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How can I include the coordinate system information from an ASTER hdf?

Tom Hart

October 19, 2012 15:24

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The HDFEOS module is successful in creating an RST file format with the IDRISI default Plane Reference System.  I'd like to directly create the RST file in the WGS84/UTM projection.  GDALIDRISI was used (command below) with reference to the EPSG projection seemingly successfully identified.

The result is an RST file of the same size as the Plane Reference System file, but with no image displayed in IDRISI.  The legend correctly displays.  The following metadata does not have correct information as follows for unit distance.

file format : Idrisi Raster A.1

file title  :

data type   : byte

file type   : binary

columns     : 4980

rows        : 4200

ref. system : utm-18n

ref. units  : m

unit dist.  : 1

min. X      : -0.5

max. X      : 4979.5

min. Y      : 4200.5

max. Y      : 0.5

pos'n error : unspecified

resolution  : 1

min. value  : 0

max. value  : 255

display min : 0

display max : 255

value units : unspecified

value error : unspecified

flag value  : none

flag def'n  : none

legend cats : 0

lineage     :

comment     :

 

Command used

gdal_translate HDF4_EOS:EOS_SWATH:"C:\RemoteSensing\ASTER\AST_L1B_00306152012155003_20120616110806_22473_Merck\AST_L1B_00306152012155003_20120616110806_22473_Merck.hdf":VNIR_Swath:ImageData1  C:\RemoteSensing\ASTER\AST_L1B_00306152012155003_20120616110806_22473_Merck\AST_MERCKImageData1_1.rst -of RST -ot Byte -b 1 -a_srs EPSG:32618

and, the aux.xml file is abbreviated when compared to the plane reference system file.

<?xml version="1.0"?>

-<PAMDataset> -<PAMRasterBand band="1"> -<Metadata> <MDI key="STATISTICS\_MAXIMUM">255</MDI> <MDI key="STATISTICS\_MEAN">0</MDI> <MDI key="STATISTICS\_MINIMUM">0</MDI> <MDI key="STATISTICS\_STDDEV">0</MDI> </Metadata> </PAMRasterBand> </PAMDataset>

Can you suggest how the WGS84/UTM projection can be directly imported with the original HDF file either via the HDFEOS module or the GDAL implementation within IDRISI?  Thank you/

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2 comments

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  Clark Labs October 19, 2012 15:53

  Tom,

  Can you verify that the file did come in correctly and displays when using the HDF import in IDRISI. Is the only issue that the reference system reads plane instead of utm-18n? If this is the case, then you simply need to change the ref system entry in metadata. It was imported correctly in the correct projection, just not documented correctly in metadata.

   

  Looking at the rdc file you posted, the min and max X and Y are incorrect. The value units entry is not the issue. There is a problem with GDAL version 1.4, which we distribute with Selva that results in this specific error with some import routines. You can try to download version 1.6 from the GDAL site and see if this resolves the issue. We will be distributing 1.6 in future releases.

  James Toledano

  Clark Labs

• 0
  
  Tom Hart October 19, 2012 19:57

  Thank you James for your suggestions. 

  Translating the HDR file to an RST with the Plane Reference System works without issue.  The ASTER WGS84/UTM projection was not translating correctly when a projection was selected as you noted.

  I was not able to get the file to accept the projection information directly using several versions of GDAL.  What I did find as a work-around is to first translate one HDR band into a GeoTIFF.  That file also did not have the correct projection, having only the row and column values for X and Y.  The GeoTIFF file was assigned the WGS84/UTM projection using GDALWarp to create a correctly registered file.  The GeoTIFF file translated to the RST format successfully using either the GDALTranslate or the GeoTIFF/IDRISI translate functions. 

  GDAL documentaton indicated that there were some issue with the HDFEOS unstructured format which may be the root cause.