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direwolf/external/geotranz/ups.c

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/********************************************************************/
/* RSC IDENTIFIER: UPS
*
*
* ABSTRACT
*
* This component provides conversions between geodetic (latitude
* and longitude) coordinates and Universal Polar Stereographic (UPS)
* projection (hemisphere, easting, and northing) coordinates.
*
*
* 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:
*
* UPS_NO_ERROR : No errors occurred in function
* UPS_LAT_ERROR : Latitude outside of valid range
* (North Pole: 83.5 to 90,
* South Pole: -79.5 to -90)
* UPS_LON_ERROR : Longitude outside of valid range
* (-180 to 360 degrees)
* UPS_HEMISPHERE_ERROR : Invalid hemisphere ('N' or 'S')
* UPS_EASTING_ERROR : Easting outside of valid range,
* (0 to 4,000,000m)
* UPS_NORTHING_ERROR : Northing outside of valid range,
* (0 to 4,000,000m)
* UPS_A_ERROR : Semi-major axis less than or equal to zero
* UPS_INV_F_ERROR : Inverse flattening outside of valid range
* (250 to 350)
*
*
* REUSE NOTES
*
* UPS is intended for reuse by any application that performs a Universal
* Polar Stereographic (UPS) projection.
*
*
* REFERENCES
*
* Further information on UPS can be found in the Reuse Manual.
*
* UPS 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
*
* UPS has no restrictions.
*
*
* ENVIRONMENT
*
* UPS 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
* ---- -----------
* 06-11-95 Original Code
* 03-01-97 Original Code
*
*
*/
/************************************************************************/
/*
* INCLUDES
*/
#include <math.h>
#include "polarst.h"
#include "ups.h"
/*
* math.h - Is needed to call the math functions.
* polar.h - Is used to convert polar stereographic coordinates
* ups.h - Defines the function prototypes for the ups module.
*/
/************************************************************************/
/* GLOBAL DECLARATIONS
*
*/
#define PI 3.14159265358979323e0 /* PI */
#define PI_OVER (PI/2.0e0) /* PI over 2 */
#define MAX_LAT ((PI * 90)/180.0) /* 90 degrees in radians */
#define MAX_ORIGIN_LAT ((81.114528 * PI) / 180.0)
#define MIN_NORTH_LAT (83.5*PI/180.0)
#define MIN_SOUTH_LAT (-79.5*PI/180.0)
#define MIN_EAST_NORTH 0
#define MAX_EAST_NORTH 4000000
/* Ellipsoid Parameters, default to WGS 84 */
static double UPS_a = 6378137.0; /* Semi-major axis of ellipsoid in meters */
static double UPS_f = 1 / 298.257223563; /* Flattening of ellipsoid */
const double UPS_False_Easting = 2000000;
const double UPS_False_Northing = 2000000;
static double UPS_Origin_Latitude = MAX_ORIGIN_LAT; /*set default = North Hemisphere */
static double UPS_Origin_Longitude = 0.0;
/************************************************************************/
/* FUNCTIONS
*
*/
long Set_UPS_Parameters( double a,
double f)
{
/*
* The function SET_UPS_PARAMETERS receives the ellipsoid parameters and sets
* the corresponding state variables. If any errors occur, the error code(s)
* are returned by the function, otherwise UPS_NO_ERROR is returned.
*
* a : Semi-major axis of ellipsoid in meters (input)
* f : Flattening of ellipsoid (input)
*/
double inv_f = 1 / f;
long Error_Code = UPS_NO_ERROR;
if (a <= 0.0)
{ /* Semi-major axis must be greater than zero */
Error_Code |= UPS_A_ERROR;
}
if ((inv_f < 250) || (inv_f > 350))
{ /* Inverse flattening must be between 250 and 350 */
Error_Code |= UPS_INV_F_ERROR;
}
if (!Error_Code)
{ /* no errors */
UPS_a = a;
UPS_f = f;
}
return (Error_Code);
} /* END of Set_UPS_Parameters */
void Get_UPS_Parameters( double *a,
double *f)
{
/*
* The function Get_UPS_Parameters returns the current ellipsoid parameters.
*
* a : Semi-major axis of ellipsoid, in meters (output)
* f : Flattening of ellipsoid (output)
*/
*a = UPS_a;
*f = UPS_f;
return;
} /* END OF Get_UPS_Parameters */
long Convert_Geodetic_To_UPS ( double Latitude,
double Longitude,
char *Hemisphere,
double *Easting,
double *Northing)
{
/*
* The function Convert_Geodetic_To_UPS converts geodetic (latitude and
* longitude) coordinates to UPS (hemisphere, easting, and northing)
* coordinates, according to the current ellipsoid parameters. If any
* errors occur, the error code(s) are returned by the function,
* otherwide UPS_NO_ERROR is returned.
*
* Latitude : Latitude in radians (input)
* Longitude : Longitude in radians (input)
* Hemisphere : Hemisphere either 'N' or 'S' (output)
* Easting : Easting/X in meters (output)
* Northing : Northing/Y in meters (output)
*/
double tempEasting, tempNorthing;
long Error_Code = UPS_NO_ERROR;
if ((Latitude < -MAX_LAT) || (Latitude > MAX_LAT))
{ /* latitude out of range */
Error_Code |= UPS_LAT_ERROR;
}
if ((Latitude < 0) && (Latitude > MIN_SOUTH_LAT))
Error_Code |= UPS_LAT_ERROR;
if ((Latitude >= 0) && (Latitude < MIN_NORTH_LAT))
Error_Code |= UPS_LAT_ERROR;
if ((Longitude < -PI) || (Longitude > (2 * PI)))
{ /* slam out of range */
Error_Code |= UPS_LON_ERROR;
}
if (!Error_Code)
{ /* no errors */
if (Latitude < 0)
{
UPS_Origin_Latitude = -MAX_ORIGIN_LAT;
*Hemisphere = 'S';
}
else
{
UPS_Origin_Latitude = MAX_ORIGIN_LAT;
*Hemisphere = 'N';
}
Set_Polar_Stereographic_Parameters( UPS_a,
UPS_f,
UPS_Origin_Latitude,
UPS_Origin_Longitude,
UPS_False_Easting,
UPS_False_Northing);
Convert_Geodetic_To_Polar_Stereographic(Latitude,
Longitude,
&tempEasting,
&tempNorthing);
*Easting = tempEasting;
*Northing = tempNorthing;
} /* END of if(!Error_Code) */
return Error_Code;
} /* END OF Convert_Geodetic_To_UPS */
long Convert_UPS_To_Geodetic(char Hemisphere,
double Easting,
double Northing,
double *Latitude,
double *Longitude)
{
/*
* The function Convert_UPS_To_Geodetic converts UPS (hemisphere, easting,
* and northing) coordinates to geodetic (latitude and longitude) coordinates
* according to the current ellipsoid parameters. If any errors occur, the
* error code(s) are returned by the function, otherwise UPS_NO_ERROR is
* returned.
*
* Hemisphere : Hemisphere either 'N' or 'S' (input)
* Easting : Easting/X in meters (input)
* Northing : Northing/Y in meters (input)
* Latitude : Latitude in radians (output)
* Longitude : Longitude in radians (output)
*/
long Error_Code = UPS_NO_ERROR;
if ((Hemisphere != 'N') && (Hemisphere != 'S'))
Error_Code |= UPS_HEMISPHERE_ERROR;
if ((Easting < MIN_EAST_NORTH) || (Easting > MAX_EAST_NORTH))
Error_Code |= UPS_EASTING_ERROR;
if ((Northing < MIN_EAST_NORTH) || (Northing > MAX_EAST_NORTH))
Error_Code |= UPS_NORTHING_ERROR;
if (Hemisphere =='N')
{UPS_Origin_Latitude = MAX_ORIGIN_LAT;}
if (Hemisphere =='S')
{UPS_Origin_Latitude = -MAX_ORIGIN_LAT;}
if (!Error_Code)
{ /* no errors */
Set_Polar_Stereographic_Parameters( UPS_a,
UPS_f,
UPS_Origin_Latitude,
UPS_Origin_Longitude,
UPS_False_Easting,
UPS_False_Northing);
Convert_Polar_Stereographic_To_Geodetic( Easting,
Northing,
Latitude,
Longitude);
if ((*Latitude < 0) && (*Latitude > MIN_SOUTH_LAT))
Error_Code |= UPS_LAT_ERROR;
if ((*Latitude >= 0) && (*Latitude < MIN_NORTH_LAT))
Error_Code |= UPS_LAT_ERROR;
} /* END OF if(!Error_Code) */
return (Error_Code);
} /* END OF Convert_UPS_To_Geodetic */
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