[gdal-dev] gdalinfo, map unit DD and epsg:9108

yrrman yrrman yrrman at gmail.com
Mon Nov 15 04:06:30 EST 2010


Hi everyone,

I'm new to this list and would therefore like to say "hello and thanks
for gdal" in the first place :-)


I just came across a minor problem where I would like to ask for your advice -

the Global Landcover set GLC2000 is available in grid format from [0].
Associated with it is the .hdr file with the projection description
[2].

Apparently the map units are in decimal degree.

When I ask gdalinfo, I get the WKT description of the SRS, see [3]


Everything's fine with this, I only came across the UNIT-Field

  UNIT["degree",0.0174532925199433, AUTHORITY["EPSG","9108"]],

where the unit is degree, defined according to epsg:9108. When you
look up epsg:9108 in the epsg registry [1] you get as Unit of Measure:

Code: EPSG::9108 - Name: degree minute second hemisphere (i.e. not
decimal degree)

Shouldn't this rather be epsg:9102 then?
Code: EPSG::9102 Name: degree, 1 degree: 0.017453292519943278 radian



As I said, it's not very important, just out of curiousity.

I'm using
GDAL 1.7.0b2, FWTools 2.4.7, released 2010/01/19


Thanks a lot and kind regards,


Chris

PS
I had sent this mail 4 days ago after some problems with registering
("googlemail" vs. "gmail"), however the mail was then neither rejected
nor appeared on the list. I now completely switched to "gmail" and
hope it will work now. Or is this list moderated and the mail has been
silently rejected? :-) Thanks again to Frank who helped with the
registration problem -  and greetings, Chris.


-------------------------------------------------------------------------------------
[0] http://bioval.jrc.ec.europa.eu/products/glc2000/products.php
[1] http://www.epsg-registry.org/
[2] glc2000_v1_1_projinfo.hdr:

BANDS:      1
ROWS:   16353
COLS:   40320
INTERLEAVING:    NA
DATATYPE: U8
BYTE_ORDER: NA
UL_X_COORDINATE:           -180.000000
UL_Y_COORDINATE:             89.991071
LR_X_COORDINATE:            179.991070
LR_Y_COORDINATE:            -56.008928
PIXEL_WIDTH:               0.0089285714
PIXEL_HEIGHT:              0.0089285714
MAP_UNITS:    DD
PROJECTION_NAME: Geographic (Lat/Lon)
PROJECTION_ZONE:     0
PROJECTION_PARAMETERS:
                   0.000000
                   0.000000
                   0.000000
                   0.000000
                   0.000000
                   0.000000
                   0.000000
                   0.000000
                   0.000000
                   0.000000
                   0.000000
                   0.000000
                   0.000000
                   0.000000
                   0.000000
SPHEROID_NAME: WGS 84
SEMI_MAJOR_AXIS:        6378137.000000
SEMI_MINOR_AXIS:        6356752.314245
E_SQUARED:                    0.006694
RADIUS:                 6371007.180918

[3] gdalinfo output:
Driver: AIG/Arc/Info Binary Grid
Files: glc2000_v1_1
     glc2000_v1_1\dblbnd.adf
     glc2000_v1_1\hdr.adf
     glc2000_v1_1\log
     glc2000_v1_1\metadata.xml
     glc2000_v1_1\prj.adf
     glc2000_v1_1\sta.adf
     glc2000_v1_1\vat.adf
     glc2000_v1_1\w001001.adf
     glc2000_v1_1\w001001x.adf
Size is 40320, 16353
Coordinate System is:
GEOGCS["WGS 84",
  DATUM["WGS_1984",
      SPHEROID["WGS 84",6378137,298.257223563,
          AUTHORITY["EPSG","7030"]],
      TOWGS84[0,0,0,0,0,0,0],
      AUTHORITY["EPSG","6326"]],
  PRIMEM["Greenwich",0,
      AUTHORITY["EPSG","8901"]],
  UNIT["degree",0.0174532925199433,
      AUTHORITY["EPSG","9108"]],
  AUTHORITY["EPSG","4326"]]
Origin = (-180.004464285700010,89.995535666300043)
Pixel Size = (0.008928571400000,-0.008928571400000)
Corner Coordinates:
Upper Left  (-180.0044643,  89.9955357) (180d 0'16.07"W, 89d59'43.93"N)
Lower Left  (-180.0044643, -56.0133924) (180d 0'16.07"W, 56d 0'48.21"S)
Upper Right ( 179.9955346,  89.9955357) (179d59'43.92"E, 89d59'43.93"N)
Lower Right ( 179.9955346, -56.0133924) (179d59'43.92"E, 56d 0'48.21"S)
Center      (  -0.0044649,  16.9910716) (  0d 0'16.07"W, 16d59'27.86"N)
Band 1 Block=256x4 Type=Byte, ColorInterp=Palette
 Min=1.000 Max=23.000
 NoData Value=255
 Metadata:
  LAYER_TYPE=thematic
 Color Table (RGB with 256 entries)
  0: 0,0,0,255 [..]


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