Krovak Oblique Conformal Conic projection (EPSG code 9819). This projection is used in the Czech
Republic and Slovakia under the name "Krovak" projection. The geographic coordinates on the
ellipsoid are first reduced to conformal coordinates on the conformal (Gaussian) sphere. These
spherical coordinates are then projected onto the oblique cone and converted to grid coordinates.
The pseudo standard parallel is defined on the conformal sphere after its rotation, to obtain the
oblique aspect of the projection. It is then the parallel on this sphere at which the map
projection is true to scale; on the ellipsoid it maps as a complex curve.
The compulsory parameters are just the ellipsoid characteristics. All other parameters are
optional and have defaults to match the common usage with Krovak projection.
In general the axis of Krovak projection are defined as westing and southing (not easting and
northing) and they are also reverted, so if the value of projected coordinates should (and in
y, x order in Krovak) be positive the 'Axis' parameter for projection
should be defined explicitly like this (in wkt):
PROJCS["S-JTSK (Ferro) / Krovak",
.
.
.
PROJECTION["Krovak"]
PARAMETER["semi_major", 6377397.155],
PARAMETER["semi_minor", 6356078.963],
UNIT["meter",1.0],
AXIS["x", WEST],
AXIS["y", SOUTH]]
Axis in Krovak:
y
By default, the axis are 'easting, northing' so the values of projected coordinates are negative
(and in y, x order in Krovak - it is cold Krovak GIS version).
References: