GProj library - Functions for reading datum parameters from the location database. More...

#include <unistd.h>
#include <string.h>
#include <ctype.h>
#include <stdlib.h>
#include <grass/gis.h>
#include <grass/glocale.h>
#include <grass/gprojects.h>
#include "local_proto.h"

Include dependency graph for proj/datum.c:

Go to the source code of this file.

Functions
int	GPJ_get_datum_by_name (const char name, struct gpj_datum dstruct)
	Look up a string in datum.table file to see if it is a valid datum name and if so place its information into a gpj_datum struct. More...

int	GPJ_get_default_datum_params_by_name (const char name, char *params)
	"Last resort" function to retrieve a "default" set of datum parameters for a datum (N.B. there really is no such thing as a catch-all default!) More...

int	GPJ_get_datum_params (char name, char params)
	Extract the datum transformation-related parameters for the current location. More...

int	GPJ__get_datum_params (const struct Key_Value projinfo, char datumname, char *params)
	Extract the datum transformation-related parameters from a set of general PROJ_INFO parameters. More...

struct gpj_datum_transform_list *	GPJ_get_datum_transform_by_name (const char *inputname)
	Internal function to find all possible sets of transformation parameters for a particular datum. More...

void	GPJ_free_datum_transform (struct gpj_datum_transform_list *item)
	Free the memory used by a gpj_datum_transform_list struct. More...

struct datum_list *	read_datum_table (void)
	Read the current GRASS datum.table from disk and store in memory. More...

void	GPJ_free_datum (struct gpj_datum *dstruct)
	Free the memory used for the strings in a gpj_datum struct. More...

void	free_datum_list (struct datum_list *dstruct)
	Free the memory used by a datum_list linked list structure. More...

Detailed Description

GProj library - Functions for reading datum parameters from the location database.

Author: Andreas Lange <andreas.lange rhein-main.de>, Paul Kelly <paul-grass stjohnspoint.co.uk>

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 proj/datum.c.

Function Documentation

◆ free_datum_list()

void free_datum_list ( struct datum_list * dstruct )

Free the memory used by a datum_list linked list structure.

Parameters

dstruct datum_list struct to be freed

Definition at line 410 of file proj/datum.c.

References G_free(), and NULL.

Referenced by GPJ_get_datum_by_name().

◆ GPJ__get_datum_params()

int GPJ__get_datum_params	(	const struct Key_Value *	projinfo,
		char **	datumname,
		char **	params
	)

Extract the datum transformation-related parameters from a set of general PROJ_INFO parameters.

This function can be used to test if a location's co-ordinate system set-up supports datum transformation.

Parameters

projinfo	Set of key_value pairs containing projection information in PROJ_INFO file format
datumname	Pointer to a pointer which will have memory allocated and into which a string containing the datum name (if present) will be placed. Otherwise set to NULL.
params	Pointer to a pointer which will have memory allocated and into which a string containing the datum parameters (if present) will be placed. Otherwise set to NULL.

Returns: -1 error or no datum information found, 1 only datum name found, 2 params found

Definition at line 173 of file proj/datum.c.

References G_asprintf(), G_debug(), G_find_key_value(), G_store(), and NULL.

Referenced by GPJ_get_datum_params(), and GPJ_osr_to_grass().

◆ GPJ_free_datum()

void GPJ_free_datum ( struct gpj_datum * dstruct )

Free the memory used for the strings in a gpj_datum struct.

Parameters

dstruct gpj_datum struct to be freed

Definition at line 396 of file proj/datum.c.

References gpj_datum::ellps, G_free(), gpj_datum::longname, and gpj_datum::name.

◆ GPJ_free_datum_transform()

void GPJ_free_datum_transform ( struct gpj_datum_transform_list * item )

Free the memory used by a gpj_datum_transform_list struct.

Parameters

item	gpj_datum_transform_list struct to be freed

Definition at line 323 of file proj/datum.c.

References gpj_datum_transform_list::comment, G_free(), gpj_datum_transform_list::params, and gpj_datum_transform_list::where_used.

Referenced by GPJ_get_default_datum_params_by_name().

◆ GPJ_get_datum_by_name()

int GPJ_get_datum_by_name	(	const char *	name,
		struct gpj_datum *	dstruct
	)

Look up a string in datum.table file to see if it is a valid datum name and if so place its information into a gpj_datum struct.

Parameters

name	String containing datum name to look up
dstruct	gpj_datum struct into which datum parameters will be placed if found

Returns: 1 if datum found, -1 if not

Definition at line 38 of file proj/datum.c.

References gpj_datum::dx, gpj_datum::dy, gpj_datum::dz, gpj_datum::ellps, free_datum_list(), G_store(), G_strcasecmp(), list, gpj_datum::longname, gpj_datum::name, name, NULL, and read_datum_table().

◆ GPJ_get_datum_params()

int GPJ_get_datum_params	(	char **	name,
		char **	params
	)

Extract the datum transformation-related parameters for the current location.

This function can be used to test if a location's co-ordinate system set-up supports datum transformation.

Parameters

name	Pointer to a pointer which will have memory allocated and into which a string containing the datum name (if present) will be placed. Otherwise set to NULL.
params	Pointer to a pointer which will have memory allocated and into which a string containing the datum parameters (if present) will be placed. Otherwise set to NULL.

Returns: -1 error or no datum information found, 1 only datum name found, 2 params found

Definition at line 135 of file proj/datum.c.

References G_free_key_value(), G_get_projinfo(), GPJ__get_datum_params(), and name.

◆ GPJ_get_datum_transform_by_name()

struct gpj_datum_transform_list* GPJ_get_datum_transform_by_name ( const char * inputname )

Internal function to find all possible sets of transformation parameters for a particular datum.

Parameters

inputname String containing the datum name we are going to look up parameters for

Returns: Pointer to struct gpj_datum_transform_list (a linked list containing transformation parameters), or NULL if no suitable parameters were found.

Definition at line 237 of file proj/datum.c.

References file, and GPATH_MAX.

Referenced by GPJ_get_default_datum_params_by_name().

◆ GPJ_get_default_datum_params_by_name()

int GPJ_get_default_datum_params_by_name	(	const char *	name,
		char **	params
	)

"Last resort" function to retrieve a "default" set of datum parameters for a datum (N.B. there really is no such thing as a catch-all default!)

Kind of a "last resort" function as there really is no such thing as a default set of datum transformation parameters. Only should really be used where user interaction to choose a set of parameters is not desirable. Use of this function is not likely to result in selection of the optimum set of datum transformation parameters for the location

Parameters

name	String containing GRASS datum name for which default parameters are to be retrieved
params	Pointer to a pointer which will have memory allocated and into which a string containing the datum parameters (if present) will be placed

Returns: The number of possible parameter sets GRASS knows about for this datum

Definition at line 86 of file proj/datum.c.

References count, G_store(), GPJ_free_datum_transform(), GPJ_get_datum_transform_by_name(), list, name, NULL, and gpj_datum_transform_list::params.

◆ read_datum_table()

struct datum_list* read_datum_table ( void )

Read the current GRASS datum.table from disk and store in memory.

The datum information is stored in a datum_list linked list structure.

Returns: Pointer to first datum_list element in linked list, or NULL if unable to open datum.table file

Definition at line 342 of file proj/datum.c.

References file, and GPATH_MAX.

Referenced by GPJ_get_datum_by_name().