[Gdal-dev] missing_value dods/opendap implemnetation (fix/patch) / Colormap

[Rob Cermak]

Hiya,

I spent a lot of time scratching my head wondering why missing_value 
wasn't working as described for dods/opendap.   
http://www.gdal.org/frmt_dods.html

Browsing through the code... it wasn't there.  Probably legacy from the
netcdf/hdf drivers if you open a file locally :)  Anyways, I'm not a C++
hacker, but I think I managed to add the support for missing_value.  
Makes the statistics and rasters via Mapserver/Mapscript much more usable
:)

gdalinfo -mm -stats 
"http://ak.aoos.org/opendap/nph-dods/data/NCEP_WAVES/test.nc?wdirsfc[0][y][x]"
Driver: DODS/DAP 3.x servers
Size is 155, 123
Coordinate System is `'
Origin = (-200.750000,44.625000)
Pixel Size = (0.50000000,0.25000000)
Corner Coordinates:
Upper Left  (    -200.750,      44.625) 
Lower Left  (    -200.750,      75.375) 
Upper Right (-123.2500000,  44.6250000) 
Lower Right (-123.2500000,  75.3750000) 
Center      (-162.0000000,  60.0000000) 
Band 1 Block=155x123 Type=Float64, ColorInterp=Undefined
    Computed Min/Max=0.000,359.990
  Minimum=0.000, Maximum=359.990, Mean=210.012, StdDev=112.840
  NoData Value=-999
Metadata:
  STATISTICS_MINIMUM=0
  STATISTICS_MAXIMUM=359.98999023438
  STATISTICS_MEAN=210.01167189722
  STATISTICS_STDDEV=112.83990256545

Patch for 1.3.1 (should be good for 1.3.0):

http://ak.aoos.org/data/patch/dods_miss.patch

An unpatched version 1.3.0 gives you:

Driver: DODS/DAP 3.x servers
Size is 155, 123
Coordinate System is `'
Origin = (-200.750000,44.625000)
Pixel Size = (0.50000000,0.25000000)
Corner Coordinates:
Upper Left  (    -200.750,      44.625) 
Lower Left  (    -200.750,      75.375) 
Upper Right (-123.2500000,  44.6250000) 
Lower Right (-123.2500000,  75.3750000) 
Center      (-162.0000000,  60.0000000) 
Band 1 Block=155x123 Type=Float64, ColorInterp=Undefined
    Computed Min/Max=-999.000,359.990
  Minimum=-999.000, Maximum=359.990, Mean=-212.334, StdDev=583.549
Metadata:
  STATISTICS_MINIMUM=-999
  STATISTICS_MAXIMUM=359.98999023438
  STATISTICS_MEAN=-212.33386887569
  STATISTICS_STDDEV=583.54930912611

Its going to take much longer how to figure out the Colormap...

Enjoy!

Rob
-- 
Rob Cermak : 907-474-7948 : FAX 907-474-7204 : PGP = 0x75869A6E
Alaska Ocean Observing System : Data Management 
School of Fisheries and Ocean Sciences : University of Alaska Fairbanks
cermak at sfos.uaf.edu : fnjrc1 at uaf.edu
ED9U1M7P01 at alaska.edu : cermak at alaska.edu