[Gdal-dev] EHdr/ESRI .hdr to read SRTM is no longer working

[Markus Neteler]

Joaquim,

if you add
PIXELTYPE SIGNEDINT
to the header file, it should work again.

Markus

On Tue, Apr 10, 2007 at 12:16:56PM +0100, Joaquim Luis wrote:
> Hi,
> The recipe of reading SRTMs by generating a ESRI .hdr file is no longer 
> working
> with  GDAL1.4 but it does work with 1.3.2
> The problem seams to be that data is converted to unsigned short int 
> instead of signed short int.
> 
> Joaquim Luis
> 
> 
> ---------------- With GDAL1.4.0
> 
> D:\programas\GDALB140\bin>gdalinfo -stats d:\img_samples\N18W071.hgt
> Driver: EHdr/ESRI .hdr Labelled
> Size is 1201, 1201
> Coordinate System is `'
> Origin = (-71.000416666666666,19.000416666666666)
> Pixel Size = (0.000833333333333,-0.000833333333333)
> Corner Coordinates:
> Upper Left  ( -71.0004167,  19.0004167)
> Lower Left  ( -71.0004167,  17.9995833)
> Upper Right ( -69.9995833,  19.0004167)
> Lower Right ( -69.9995833,  17.9995833)
> Center      ( -70.5000000,  18.5000000)
> Band 1 Block=1201x1 Type=UInt16, ColorInterp=Undefined
>  Minimum=0.000, Maximum=65535.000, Mean=2873.507, StdDev=11834.425
>  NoData Value=-32768
> 
> ---------------- Now with GDAL1.3.2
> 
> 
> D:\programas\GDALB132\bin>gdalinfo -stats d:\img_samples\N18W071.hgt
> Driver: EHdr/ESRI .hdr Labelled
> Size is 1201, 1201
> Coordinate System is `'
> Origin = (-71.000417,19.000417)
> Pixel Size = (0.00083333,-0.00083333)
> Corner Coordinates:
> Upper Left  ( -71.0004167,  19.0004167)
> Lower Left  ( -71.0004167,  17.9995833)
> Upper Right ( -69.9995833,  19.0004167)
> Lower Right ( -69.9995833,  17.9995833)
> Center      ( -70.5000000,  18.5000000)
> Band 1 Block=1201x1 Type=Int16, ColorInterp=Undefined
>  Minimum=-39.000, Maximum=2833.000, Mean=459.681, StdDev=572.878
>  NoData Value=-32768
>  Metadata:
>    STATISTICS_MINIMUM=-39
>    STATISTICS_MAXIMUM=2833
>    STATISTICS_MEAN=459.68081074608
>    STATISTICS_STDDEV=572.87797657624
> 
> and the header file is
> 
> # N18W071.hdr
> 
> BYTEORDER     M
> LAYOUT        BIL
> NROWS       1201
> NCOLS       1201
> NBANDS        1
> NBITS         16
> BANDROWBYTES  2402
> TOTALROWBYTES 2402
> BANDGAPBYTES  0
> NODATA        -32768
> ULXMAP        -71
> ULYMAP        19
> XDIM         0.000833333333333
> YDIM         0.000833333333333
> 

-- 
Markus Neteler  <neteler itc it>  http://mpa.itc.it/markus/
FBK-irst -  Centro per la Ricerca Scientifica e Tecnologica
MPBA - Predictive Models for Biol. & Environ. Data Analysis
Via Sommarive, 18        -       38050 Povo (Trento), Italy

------------------
ITC -> dall'1 marzo 2007 Fondazione Bruno Kessler
ITC -> since 1 March 2007 Fondazione Bruno Kessler
------------------