[Gdal-dev] Re: GDAL and Spot Vegetation

[Markus Neteler]

On Wed, Aug 18, 2004 at 05:09:13PM +0200, Vincent Schut wrote:
> On Wednesday 18 August 2004 16:56, Markus Neteler wrote:
> 
> <snip>
> >
> > So one seems to have to parse the 0001_LOG.TXT (sigh).
> 
> That's what I did...

Meanwhile I got a sort of valid VRT file constructed (manually).
Not sure yet about "Plate Caree"... I used QGIS to
overlap to VMAP0 coastline data, it matches quite well.

So here my suggestion, added the spot_vegetation_ndvi.vrt file:

gdalinfo spot_vegetation_ndvi.vrt
Driver: VRT/Virtual Raster
Size is 8177, 5601
Coordinate System is:
GEOGCS["wgs84",
    DATUM["WGS_1984",
        SPHEROID["wgs84",6378137,298.257223563],
        TOWGS84[0.000,0.000,0.000]],
    PRIMEM["Greenwich",0],
    UNIT["degree",0.0174532925199433]]
Origin = (-11.004464,75.044643)
Pixel Size = (0.00892857,-0.00892857)
Corner Coordinates:
Upper Left  ( -11.0044643,  75.0446433) ( 11d 0'16.07"W, 75d 2'40.72"N)
Lower Left  ( -11.0044643,  25.0357149) ( 11d 0'16.07"W, 25d 2'8.57"N)
Upper Right (  62.0044641,  75.0446433) ( 62d 0'16.07"E, 75d 2'40.72"N)
Lower Right (  62.0044641,  25.0357149) ( 62d 0'16.07"E, 25d 2'8.57"N)
Center      (  25.4999999,  50.0401791) ( 25d30'0.00"E, 50d 2'24.64"N)
Band 1 Block=128x128 Type=Byte, ColorInterp=Gray
  NoData Value=0

Does it look reasonable (I don't like the small deviation);
and there is the usual cell center vs cell corners story...

The file 0001/0001_LOG.TXT reports:
[...]
CARTO_UPPER_LEFT_X         -11.000000
CARTO_UPPER_LEFT_Y          75.000000
CARTO_UPPER_RIGHT_X         62.000000
CARTO_UPPER_RIGHT_Y         75.000000
CARTO_LOWER_RIGHT_X         62.000000
CARTO_LOWER_RIGHT_Y         25.000000
CARTO_LOWER_LEFT_X         -11.000000
CARTO_LOWER_LEFT_Y          25.000000
CARTO_CENTER_X              25.500000
CARTO_CENTER_Y              50.000000
CARTO_HEIGHT                50.000000
CARTO_WIDTH                 73.000000
GEO_UPPER_LEFT_LAT        +075.000000
GEO_UPPER_LEFT_LONG       -011.000000
GEO_UPPER_RIGHT_LAT       +075.000000
GEO_UPPER_RIGHT_LONG      +062.000000
GEO_LOWER_RIGHT_LAT       +025.000000
GEO_LOWER_RIGHT_LONG      +062.000000
GEO_LOWER_LEFT_LAT        +025.000000
GEO_LOWER_LEFT_LONG       -011.000000

I don't feel that the map in QGIS is shifted by 0.5 degree.
Mmh.

Please let know in case of errors in the VRT file.

Markus
-------------- next part --------------
<VRTDataset rasterXSize="8177" rasterYSize="5601">
  <SRS>GEOGCS[&quot;wgs84&quot;,DATUM[&quot;WGS_1984&quot;,SPHEROID[&quot;wgs84&quot;,6378137,298.257223563],TOWGS84[0.000,0.000,0.000]],PRIMEM[&quot;Greenwich&quot;,0],UNIT[&quot;degree&quot;,0.0174532925199433]]</SRS>
  <GeoTransform> -1.1004464285e+01,  8.9285714e-03,  0.0000000000000000e+00,  7.5044643285e+01,  0.0000000000000000e+00, -8.9285714e-03</GeoTransform>
  <VRTRasterBand dataType="Byte" band="1">
    <NoDataValue>0.00000000000000E+00</NoDataValue>
    <ColorInterp>Gray</ColorInterp>
    <SimpleSource>
      <SourceFilename>0001/0001_NDV.HDF</SourceFilename>
      <SourceBand>1</SourceBand>
      <SrcRect xOff="0" yOff="0" xSize="8177" ySize="5601"/>
      <DstRect xOff="0" yOff="0" xSize="8177" ySize="5601"/>
    </SimpleSource>
  </VRTRasterBand>
</VRTDataset>