Krovak Oblique Conic Conformal

Name Krovak Oblique Conic Conformal
EPSG Code 9819
GeoTIFF Code
OGC WKT Name Krovak
Supported By EPSG, PROJ.4, OGC WKT

Projection Parameters

Name EPSG # GeoTIFF ID OGC WKT Units Notes
Latitude of projection center 1 CenterLat latitude_of_center Angular
Longitude of projection center 2 CenterLong longitude_of_center Angular
Azimuth of the center line 3 AzimuthAngle azimuth Angular
Latitude of Pseudo Standard Parallel 4 pseudo_standard_parallel_1 Angular
Scale factor on the pseudo standard line 5 ScaleAtCenter scale_factor Unitless
False Easting 6 FalseEasting false_easting Linear
False Northing 7 FalseNorthing false_northing Linear

Notes

Krovak could be added to PROJ.4 if a CT code was assigned, and some way of transporting the latitude of pseudo standard parallel was assigned.

Test Point

Given the following Well Known Text definition of a Krovak coordinate system:

PROJCS["S-JTSK (Ferro) / Krovak",
    GEOGCS["S-JTSK (Ferro)",
        DATUM["D_S_JTSK_Ferro",
            SPHEROID["Bessel 1841",6377397.155,299.1528128]],
        PRIMEM["Ferro",-17.66666666666667],
        UNIT["degree",0.0174532925199433]],
    PROJECTION["Krovak"],
    PARAMETER["latitude_of_center",49.5],
    PARAMETER["longitude_of_center",42.5],
    PARAMETER["azimuth",30.28813972222222],
    PARAMETER["pseudo_standard_parallel_1",78.5],
    PARAMETER["scale_factor",0.9999],
    PARAMETER["false_easting",0],
    PARAMETER["false_northing",0],
    UNIT["metre",1]]
The point (16d50'59.17"E,50d12'32.44"N) relative to greenwich maps to (568991.18mE, 1050538.67mN) in the projected coordinate system. To avoid the issue of prime meridian add the prime meridian offset to the longitude_of_center.

PROJ.4 Organization

PROJ.4 has the azimuth, and pseudo standard parallel "hardcoded" to match the common use of Krovak (azimuth = 30.28813972222222, pseudo standard parallel 78.5). Other parameters default to the values in the above test point (with longitude_of_center adjusted for prime meridian).

  +proj=krovak +lat_0=Latitude of projection center 
               +lon_0=Longitude of projection center
               +k_0=Scale factor on initial line 
               +x_0=False Easting
               +y_0=False Northing