do_proj.c File Reference

GProj library - Functions for re-projecting point data. More...

#include <stdio.h>
#include <string.h>
#include <ctype.h>
#include <grass/gis.h>
#include <grass/gprojects.h>
#include <grass/glocale.h>

Include dependency graph for do_proj.c:

Go to the source code of this file.

Macros
#define	MULTIPLY_LOOP(x, y, c, m)
#define	DIVIDE_LOOP(x, y, c, m)

Functions
int	pj_do_proj (double *x, double *y, struct pj_info *info_in, struct pj_info *info_out)
	Re-project a point between two co-ordinate systems. More...
int	pj_do_transform (int count, double *x, double *y, double *h, struct pj_info *info_in, struct pj_info *info_out)
	Re-project an array of points between two co-ordinate systems with optional ellipsoidal height conversion. More...

Detailed Description

GProj library - Functions for re-projecting point data.

Author

Original Author unknown, probably Soil Conservation Service Eric Miller, Paul Kelly

(C) 2003-2008 by the GRASS Development Team

This program is free software under the GNU General Public License (>=v2). Read the file COPYING that comes with GRASS for details.

Definition in file do_proj.c.

Macro Definition Documentation

#define DIVIDE_LOOP	(		x,
			y,
			c,
			m
	)

Value:

do {\
   int i; \
   for (i = 0; i < c; ++i) {\
       x[i] /= m; \
       y[i] /= m; \
   }\
} while (0)

Definition at line 35 of file do_proj.c.

Referenced by pj_do_transform().

#define MULTIPLY_LOOP	(		x,
			y,
			c,
			m
	)

Value:

do {\
   int i; \
   for (i = 0; i < c; ++i) {\
       x[i] *= m; \
       y[i] *= m; \
   }\
} while (0)

Definition at line 26 of file do_proj.c.

Referenced by pj_do_transform().

Function Documentation

int pj_do_proj	(	double *	x,
		double *	y,
		struct pj_info *	info_in,
		struct pj_info *	info_out
	)

Re-project a point between two co-ordinate systems.

This function takes pointers to two pj_info structures as arguments, and projects a point between the co-ordinate systems represented by them. The easting and northing of the point are contained in two pointers passed to the function; these will be overwritten by the co-ordinates of the re-projected point.

Parameters

x	Pointer to a double containing easting or longitude
y	Pointer to a double containing northing or latitude
info_in	pointer to pj_info struct for input co-ordinate system
info_out	pointer to pj_info struct for output co-ordinate system

Returns

Return value from PROJ pj_transform() function

Definition at line 63 of file do_proj.c.

References G_warning(), and dialogs::h.

int pj_do_transform	(	int	count,
		double *	x,
		double *	y,
		double *	h,
		struct pj_info *	info_in,
		struct pj_info *	info_out
	)

Re-project an array of points between two co-ordinate systems with optional ellipsoidal height conversion.

This function takes pointers to two pj_info structures as arguments, and projects an array of points between the co-ordinate systems represented by them. Pointers to the three arrays of easting, northing, and ellipsoidal height of the point (this one may be NULL) are passed to the function; these will be overwritten by the co-ordinates of the re-projected points.

Parameters

count	Number of points in the arrays to be transformed
x	Pointer to an array of type double containing easting or longitude
y	Pointer to an array of type double containing northing or latitude
h	Pointer to an array of type double containing ellipsoidal height. May be null in which case a two-dimensional re-projection will be done
info_in	pointer to pj_info struct for input co-ordinate system
info_out	pointer to pj_info struct for output co-ordinate system

Returns

Return value from PROJ pj_transform() function

Definition at line 134 of file do_proj.c.

References count, DIVIDE_LOOP, G_free(), G_warning(), MULTIPLY_LOOP, and NULL.