[Gdal-dev] processing SRTM-3?

Joaquim Luis jluis at ualg.pt
Thu Jul 29 13:39:21 EDT 2004


> Is there an action item here?  Should it be reporting GEOGCS[]?  Is this
> an ESRI BIL file?  What is in the .hdr?  Is there a .prj file?

Frank,
Sorry, I'll try to be more clear now.
I am using the Markus trick to read SRTM files. The trick consists in generating a
.hdr
In my example case, the .hdr has

BYTEORDER     M
LAYOUT        BIL
NROWS         1201
NCOLS         1201
NBANDS        1
NBITS         16
BANDROWBYTES  2402
TOTALROWBYTES 2402
BANDGAPBYTES  0
NODATA        -32768
ULXMAP        -9
ULYMAP        38
XDIM          0.000833333333333
YDIM          0.000833333333333

runing gdalinfo used to produce an output like this

Driver: EHdr/ESRI .hdr Labelled
Size is 1201, 1201
Coordinate System is:
GEOGCS["wgs84",  DATUM["WGS_1984",
SPHEROID["wgs84",6378137,298.257223563],
TOWGS84[0.000000,0.000000,0.000000]],
PRIMEM["Greenwich",0],
UNIT["degree",0.0174532925199433]]
Origin = (-9.000417,38.000417)
Pixel Size = (0.00083333,-0.00083333)
Corner Coordinates:
Upper Left  (  -9.0004167,  38.0004167)
Lower Left  (  -9.0004167,  36.9995833)
Upper Right (  -7.9995833,  38.0004167)
Lower Right (  -7.9995833,  36.9995833)
Center      (  -8.5000000,  37.5000000)
Band 1 Block=1201x1 Type=Int16, ColorInterp=Undefined
    Computed Min/Max=-49.000,896.000
  NoData Value=-32768

but now I only get

Driver: EHdr/ESRI .hdr Labelled
Size is 1201, 1201
Coordinate System is `'                                <================= (empty)
Origin = (-9.000417,38.000417)
Pixel Size = (0.00083333,-0.00083333)
Corner Coordinates:
Upper Left  (  -9.0004167,  38.0004167)
Lower Left  (  -9.0004167,  36.9995833)
Upper Right (  -7.9995833,  38.0004167)
Lower Right (  -7.9995833,  36.9995833)
Center      (  -8.5000000,  37.5000000)
Band 1 Block=1201x1 Type=Int16, ColorInterp=Undefined
    Computed Min/Max=-49.000,896.000
  NoData Value=-32768

> > However, gdalinfo of a ENVI or USGS SDST files those lines are reported.
>
> Good.  It was you that reported the problem with the ENVI files not reporting
> the coordinate system properly, right?

No, but it was because of it that I decided to do a cvs.

Thanks
Joaquim Luis





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