tranmerc.h

#ifndef TRANMERC_H
  #define TRANMERC_H

/***************************************************************************/
/* RSC IDENTIFIER: TRANSVERSE MERCATOR
 *
 * ABSTRACT
 *
 *    This component provides conversions between Geodetic coordinates 
 *    (latitude and longitude) and Transverse Mercator projection coordinates
 *    (easting and northing).
 *
 * ERROR HANDLING
 *
 *    This component checks parameters for valid values.  If an invalid value
 *    is found the error code is combined with the current error code using 
 *    the bitwise or.  This combining allows multiple error codes to be
 *    returned. The possible error codes are:
 *
 *       TRANMERC_NO_ERROR           : No errors occurred in function
 *       TRANMERC_LAT_ERROR          : Latitude outside of valid range
 *                                      (-90 to 90 degrees)
 *       TRANMERC_LON_ERROR          : Longitude outside of valid range
 *                                      (-180 to 360 degrees, and within
 *                                        +/-90 of Central Meridian)
 *       TRANMERC_EASTING_ERROR      : Easting outside of valid range
 *                                      (depending on ellipsoid and
 *                                       projection parameters)
 *       TRANMERC_NORTHING_ERROR     : Northing outside of valid range
 *                                      (depending on ellipsoid and
 *                                       projection parameters)
 *       TRANMERC_ORIGIN_LAT_ERROR   : Origin latitude outside of valid range
 *                                      (-90 to 90 degrees)
 *       TRANMERC_CENT_MER_ERROR     : Central meridian outside of valid range
 *                                      (-180 to 360 degrees)
 *       TRANMERC_A_ERROR            : Semi-major axis less than or equal to zero
 *       TRANMERC_INV_F_ERROR        : Inverse flattening outside of valid range
 *								  	                  (250 to 350)
 *       TRANMERC_SCALE_FACTOR_ERROR : Scale factor outside of valid
 *                                     range (0.3 to 3.0)
 *		 TM_LON_WARNING              : Distortion will result if longitude is more
 *                                      than 9 degrees from the Central Meridian
 *
 * REUSE NOTES
 *
 *    TRANSVERSE MERCATOR is intended for reuse by any application that 
 *    performs a Transverse Mercator projection or its inverse.
 *    
 * REFERENCES
 *
 *    Further information on TRANSVERSE MERCATOR can be found in the 
 *    Reuse Manual.
 *
 *    TRANSVERSE MERCATOR originated from :  
 *                      U.S. Army Topographic Engineering Center
 *                      Geospatial Information Division
 *                      7701 Telegraph Road
 *                      Alexandria, VA  22310-3864
 *
 * LICENSES
 *
 *    None apply to this component.
 *
 * RESTRICTIONS
 *
 *    TRANSVERSE MERCATOR has no restrictions.
 *
 * ENVIRONMENT
 *
 *    TRANSVERSE MERCATOR was tested and certified in the following 
 *    environments:
 *
 *    1. Solaris 2.5 with GCC, version 2.8.1
 *    2. Windows 95 with MS Visual C++, version 6
 *
 * MODIFICATIONS
 *
 *    Date              Description
 *    ----              -----------
 *    10-02-97          Original Code
 *    03-02-97          Re-engineered Code
 *
 */


/***************************************************************************/
/*
 *                              DEFINES
 */

  #define TRANMERC_NO_ERROR           0x0000
  #define TRANMERC_LAT_ERROR          0x0001
  #define TRANMERC_LON_ERROR          0x0002
  #define TRANMERC_EASTING_ERROR      0x0004
  #define TRANMERC_NORTHING_ERROR     0x0008
  #define TRANMERC_ORIGIN_LAT_ERROR   0x0010
  #define TRANMERC_CENT_MER_ERROR     0x0020
  #define TRANMERC_A_ERROR            0x0040
  #define TRANMERC_INV_F_ERROR        0x0080
  #define TRANMERC_SCALE_FACTOR_ERROR 0x0100
  #define TRANMERC_LON_WARNING        0x0200


/***************************************************************************/
/*
 *                              FUNCTION PROTOTYPES
 *                                for TRANMERC.C
 */

/* ensure proper linkage to c++ programs */
  #ifdef __cplusplus
extern "C" {
  #endif


  long Set_Transverse_Mercator_Parameters(double a,      
                                          double f,
                                          double Origin_Latitude,
                                          double Central_Meridian,
                                          double False_Easting,
                                          double False_Northing,
                                          double Scale_Factor);
/*
 * The function Set_Tranverse_Mercator_Parameters receives the ellipsoid
 * parameters and Tranverse Mercator projection parameters as inputs, and
 * sets the corresponding state variables. If any errors occur, the error
 * code(s) are returned by the function, otherwise TRANMERC_NO_ERROR is
 * returned.
 *
 *    a                 : Semi-major axis of ellipsoid, in meters    (input)
 *    f                 : Flattening of ellipsoid                    (input)
 *    Origin_Latitude   : Latitude in radians at the origin of the   (input)
 *                         projection
 *    Central_Meridian  : Longitude in radians at the center of the  (input)
 *                         projection
 *    False_Easting     : Easting/X at the center of the projection  (input)
 *    False_Northing    : Northing/Y at the center of the projection (input)
 *    Scale_Factor      : Projection scale factor                    (input) 
 */


  void Get_Transverse_Mercator_Parameters(double *a,
                                          double *f,
                                          double *Origin_Latitude,
                                          double *Central_Meridian,
                                          double *False_Easting,
                                          double *False_Northing,
                                          double *Scale_Factor);
/*
 * The function Get_Transverse_Mercator_Parameters returns the current
 * ellipsoid and Transverse Mercator projection parameters.
 *
 *    a                 : Semi-major axis of ellipsoid, in meters    (output)
 *    f                 : Flattening of ellipsoid                    (output)
 *    Origin_Latitude   : Latitude in radians at the origin of the   (output)
 *                         projection
 *    Central_Meridian  : Longitude in radians at the center of the  (output)
 *                         projection
 *    False_Easting     : Easting/X at the center of the projection  (output)
 *    False_Northing    : Northing/Y at the center of the projection (output)
 *    Scale_Factor      : Projection scale factor                    (output) 
 */


  long Convert_Geodetic_To_Transverse_Mercator (double Latitude,
                                                double Longitude,
                                                double *Easting,
                                                double *Northing);

/*
 * The function Convert_Geodetic_To_Transverse_Mercator converts geodetic
 * (latitude and longitude) coordinates to Transverse Mercator projection
 * (easting and northing) coordinates, according to the current ellipsoid
 * and Transverse Mercator projection coordinates.  If any errors occur, the
 * error code(s) are returned by the function, otherwise TRANMERC_NO_ERROR is
 * returned.
 *
 *    Latitude      : Latitude in radians                         (input)
 *    Longitude     : Longitude in radians                        (input)
 *    Easting       : Easting/X in meters                         (output)
 *    Northing      : Northing/Y in meters                        (output)
 */


  long Convert_Transverse_Mercator_To_Geodetic (double Easting,
                                                double Northing,
                                                double *Latitude,
                                                double *Longitude);

/*
 * The function Convert_Transverse_Mercator_To_Geodetic converts Transverse
 * Mercator projection (easting and northing) coordinates to geodetic
 * (latitude and longitude) coordinates, according to the current ellipsoid
 * and Transverse Mercator projection parameters.  If any errors occur, the
 * error code(s) are returned by the function, otherwise TRANMERC_NO_ERROR is
 * returned.
 *
 *    Easting       : Easting/X in meters                         (input)
 *    Northing      : Northing/Y in meters                        (input)
 *    Latitude      : Latitude in radians                         (output)
 *    Longitude     : Longitude in radians                        (output)
 */


  #ifdef __cplusplus
}
  #endif

#endif /* TRANMERC_H */