Krovak

Classification: Conformal Conical

Available forms: Forward and inverse, spherical and ellipsoidal

Defined area: Global, but more accurate around Czech Republic and Slovakia

Alias: krovak

Domain: 2D

Input type: Geodetic coordinates

Output type: Projected coordinates

Projection String

+proj=krovak
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By default, coordinates in the forward direction are output in easting, northing, and negative in the Czech Republic and Slovakia, with absolute value of easting/westing being smaller than absolute value of northing/southing.

See also mod_krovak for a variation of Krovak used with the S-JTSK/05 datum in the Czech Republic.

Required Parameters

• None, all parameters are optional for this projection.

Optional Parameters

• +czech: Reverses the sign of the output coordinates for use in the Czech Republic and Slovakia (positive values become westing and southing).
• +lon_0: Longitude of projection center. Defaults to 24°50' (24.8333).
• +lat_0: Latitude of projection center. Defaults to 49.5.
• +k_0: Scale factor. Defaults to 0.9999.
• +x_0: False easting. Defaults to 0.
• +y_0: False northing. Defaults to 0.

Notes

• The latitude of the pseudo standard parallel is hardcoded to 78.5°.
• The ellipsoid used is Bessel by default.
• Before PROJ 9.4, using custom x_0 or y_0 without the +czech switch resulted in incorrect values.