[Gdal-dev] AAIGrid driver: small PROJCS detection problem

[Markus Neteler]

Hello,

I have a small "problem" (?) with an ASCII DEM which comes
with a .prj file:

cat dgm_20mfill_ascii.prj
Projection    TRANSVERSE
Zunits        NO
Units         METERS
Datum         MOD
Spheroid      INTERNATIONAL1909
Xshift        -1000000.0000000000
Yshift        -5000000.0000000000
Parameters
0.9996 /* scale factor at central meridian
 9  0  0.000 /* longitude of central meridian
 0  0  0.000 /* latitude of origin
1500000.00000 /* false easting (meters)
0.00000 /* false northing (meters)

gdalinfo dgm_20mfill_ascii
Driver: AAIGrid/Arc/Info ASCII Grid
Size is 8184, 5159
Coordinate System is:
PROJCS["unnamed",
    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"]],
        AXIS["Lat",NORTH],
        AXIS["Long",EAST],
        AUTHORITY["EPSG","4326"]],
    PROJECTION["Transverse_Mercator"],
    PARAMETER["latitude_of_origin",9],
    PARAMETER["central_meridian",0],
    PARAMETER["scale_factor",0.9996],
    PARAMETER["false_easting",1500000],
    PARAMETER["false_northing",0],
    UNIT["METERS",1]]
Origin = (604170.000000,221410.000000)
Pixel Size = (20.00000000,-20.00000000)
Corner Coordinates:
Upper Left  (  604170.000,  221410.000) (  8d10'16.75"W, 10d53'34.18"N)
Lower Left  (  604170.000,  118230.000) (  8d 8'49.54"W,  9d58'8.90"N)
Upper Right (  767850.000,  221410.000) (  6d41'10.18"W, 10d55'44.61"N)
Lower Right (  767850.000,  118230.000) (  6d39'58.50"W, 10d 0'8.04"N)
Center      (  686010.000,  169820.000) (  7d25'5.15"W, 10d26'57.03"N)
Band 1 Block=8184x1 Type=Int16, ColorInterp=Undefined
  NoData Value=-9999


The PROJCS is set "unnamed", shouldn't it be Transverse_Mercator
or is the problem related to the fact that the projection is
very particular? It should be the Italian Gauss-Boaga, but
the modified version from the Province of Bolzano. Note the
Xshift        -1000000.0000000000
Yshift        -5000000.0000000000

which is probably ignored (the center should be around
Center Longitude: 11:25:49.77287E [11.43049]
Center latitude:  46:39:01.079651N [46.65030]
).

So maybe there are two problems?


Thanks for any hint,

 Markus

PS:
The header of the ASCII file looks like this:

ncols         8184
nrows         5159
xllcorner     604170
yllcorner     118230
cellsize      20
NODATA_value  -9999
-9999 -9999 -9999 ...