xxxinv - Transforms input Easting and Northing to longitude and latitude for the xxx projection

SYNTAX

FUNCTION xxxinv (x, y, lon, lat) 
    double x;
    double y;
    double *lon;
    double *lat;

PARAMETERS

x (input, double)

Easting value. Value given in meters.

y (input, double)

Northing value. Value given in meters.

lon (output, double)

Output longitude. Value given in radians.

lat (output, double)

Output latitude. Value given in radians.

DESCRIPTION

xxxinv() converts input Easting and Northing to the corresponding longitude and latitude for the xxx projection (xxx is replaced by the abbreviation of the projection). The following subroutines follow this general format: 
     utminv(x, y, lon, lat)     -- Universal Transverse Mercator (UTM)
     stplninv(x, y, lon, lat)   -- State Plane
     alberinv(x, y, lon, lat)   -- Albers
     lamccinv(x, y, lon, lat)   -- Lambert Conformal Conic
     merinv(x, y, lon, lat)     -- Mercator
     psinv(x, y, lon, lat)      -- Polar Stereographic
     polyinv(x, y, lon, lat)    -- Polyconic
     eqconinv(x, y, lon, lat)   -- Equidistant Conic
     tminv(x, y, lon, lat)      -- Transverse Mercator (TM)
     sterinv(x, y, lon, lat)    -- Stereographic
     lamazinv(x, y, lon, lat)   -- Lambert Azimuthal
     aziminv(x, y, lon, lat)    -- Azimuthal Equidistant
     gnominv(x, y, lon, lat)    -- Gnomonic
     orthinv(x, y, lon, lat)    -- Orthographic
     gvnspinv(x, y, lon, lat)   -- General Near Side Perspective
     sininv(x, y, lon, lat)     -- Sinusoidal
     equiinv(x, y, lon, lat)    -- Equirectangular
     millinv(x, y, lon, lat)    -- Miller
     vandginv(x, y, lon, lat)   -- Van der Grinten
     omerinv(x, y, lon, lat)    -- Hotine Oblique Mercator (HOM)
     robinv(x, y, lon, lat)     -- Robinson
     sominv(x, y, lon, lat)     -- Space Oblique Mercator (SOM)
     alconinv(x, y, lon, lat)   -- Alaska Conformal
     goodinv(x, y, lon, lat)    -- Goode
     molwinv(x, y, lon, lat)    -- Mollweide
     imolwinv(x, y, lon, lat)   -- Interrupted Mollweide
     haminv(x, y, lon, lat)     -- Hammer
     wivinv(x, y, lon, lat)     -- Wagner IV
     wviiinv(x, y, lon, lat)    -- Wagner VII
     obleqinv(x, y, lon, lat)   -- Oblated Equal Area
init_inv() must be called once before calling any of the above subroutines. For example, if utminv() is to be called, init_inv() must be called setting the UTM projection, UTM zone, and ellipsoid. Then utminv() may be called as many times as needed even if init_inv() is called initializing another projection. The only exception is if init_inv() is called initializing UTM with another zone or ellipsoid, then init_inv() must be called again to perform the original conversion.

RETURN VALUE

xxxinv() returns

    E_SUCC   (0)  --> Successful completion
    ERROR    (>0) --> An error was encountered
    IN_BREAK (-2) --> Coordinates fell into interrupted area

SPECIAL CONSIDERATIONS:

The xxxinv() call is for C only.