ASRP polar arc zone images are not correctly georeferenced

[steveb]

When ASRP polar arc zone images are opened the affine transformation coefficients are not set correctly. The cell size is always set to 500m and the image origin to (-1152000, 1152000).

The following method can be used to calculate the affine transformation coefficients for polar arc zone images:

if( ZNA == 9)
{
// North Polar Case
    padfGeoTransform[0] = 111319.4907933 * (90.0 – PSO/3600.0) * sin(LSO * PI / 648000.0);
    padfGeoTransform[1] = 40075016.68558 / ARV;
    padfGeoTransform[2] = 0.0;
    padfGeoTransform[3] = -111319.4907933 * (90.0 – PSO/3600.0) * cos(LSO * PI / 648000.0);
    padfGeoTransform[4] = 0.0;
    padfGeoTransform[5] = -40075016.68558 / ARV;
}
else if (ZNA == 18)
{
// South Polar Case
    padfGeoTransform[0] = 111319.4907933 * (90.0 + PSO/3600.0) * sin(LSO * PI / 648000.0);
    padfGeoTransform[1] = 40075016.68558 / ARV;
    padfGeoTransform[2] = 0.0;
    padfGeoTransform[3] = 111319.4907933 * (90.0 + PSO/3600.0) * cos(LSO * PI / 648000.0);
    padfGeoTransform[4] = 0.0;
    padfGeoTransform[5] = -40075016.68558 / ARV;
}

The method used is based on a sphere of radius 6378137m in accordance with the ASRP specification. In addition the polar zone coordinate system definitions will need to be modified as follows:

if( ZNA == 9 )
{
    osSRS = "PROJCS[\"ARC_System_Zone_09\",GEOGCS[\"GCS_Sphere\",DATUM[\"D_Sphere\",SPHEROID[\"Sphere\",6378137.0,0.0]],PRIMEM[\"Greenwich\",0],UNIT[\"degree\",0.0174532925199433]],PROJECTION[\"Azimuthal_Equidistant\"],PARAMETER[\"latitude_of_center\",90],PARAMETER[\"longitude_of_center\",0],PARAMETER[\"false_easting\",0],PARAMETER[\"false_northing\",0]]";
}

if (ZNA == 18)
{
    osSRS = "PROJCS[\"ARC_System_Zone_18\",GEOGCS[\"GCS_Sphere\",DATUM[\"D_Sphere\",SPHEROID[\"Sphere\",6378137.0,0.0]],PRIMEM[\"Greenwich\",0],UNIT[\"degree\",0.0174532925199433]],PROJECTION[\"Azimuthal_Equidistant\"],PARAMETER[\"latitude_of_center\",-90],PARAMETER[\"longitude_of_center\",0],PARAMETER[\"false_easting\",0],PARAMETER[\"false_northing\",0]]";
}

The attached zip file contains 3 ASRP polar test datasets. The cell size and origin of the test images are given in the following table.

Dataset	Cell Size X	Cell Size Y	Origin X	Origin Y
TEST0101	100.0914539	100.0914539	-307480.946	-179363.885
TEST0201	100.0914539	100.0914539	115305.354	153740.473
TEST0501	100.0914539	100.0914539	-307480.946	153740.473

[steveb]

ASRP Polar Test Data

[Even Rouault]

In 34457:

ASRP: fix georeferencing of polar arc zone images (patch by steveb, fixes #6560)

[Even Rouault]

In 34458:

ASRP: fix georeferencing of polar arc zone images (patch by steveb, fixes #6560)