proj/datum.c File Reference

#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 (struct Key_Value *projinfo, char **datumname, char **params)
	Extract the datum transformation-related parameters from a set of general PROJ_INFO parameters. More...
int	GPJ_ask_datum_params (const char *datumname, char **params)
	Interactively ask for datum parameters for a particular datum. 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...

Function Documentation

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 557 of file proj/datum.c.

References datum_list::ellps, G_free(), datum_list::longname, datum_list::name, datum_list::next, NULL, and old.

Referenced by GPJ_get_datum_by_name(), and GPJ_osr_to_grass().

int GPJ__get_datum_params	(	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_find_key_value(), G_gisbase(), G_store(), forms::gisbase, and NULL.

Referenced by GPJ_get_datum_params(), GPJ_grass_to_osr(), GPJ_osr_to_grass(), and pj_get_kv().

int GPJ_ask_datum_params	(	const char *	datumname,
		char **	params
	)

Interactively ask for datum parameters for a particular datum.

Uses traditional GRASS interactive prompt interface to provide information to user and encourage him/her to select the most appropriate set of datum transformation parameters for the location. Could really benefit from an abstracted user interaction library for seamless GUI interaction.

Parameters

datumname	String containing datum name that parameters are to be found for. Must exist in datum.table or be "custom"
params	Pointer to a pointer that will have memory allocated and into which a string containing the datum parameters chosen by the user will be placed.

Returns

1 ok, -1 error or user cancelled

Definition at line 239 of file proj/datum.c.

References buff, fclose(), G_asprintf(), G_convert_dirseps_to_host(), G_free(), G_gets(), G_strcasecmp(), G_strip(), G_system(), G_tempfile(), G_warning(), G_yes(), getenv(), GPJ_get_datum_transform_by_name(), NULL, old, and sprintf().

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 543 of file proj/datum.c.

References G_free().

Referenced by GPJ__get_ellipsoid_params(), GPJ_get_datum_transform_by_name(), GPJ_grass_to_osr(), and GPJ_osr_to_grass().

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 466 of file proj/datum.c.

References G_free().

Referenced by GPJ_get_default_datum_params_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 37 of file proj/datum.c.

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

Referenced by GPJ__get_ellipsoid_params(), GPJ_get_datum_transform_by_name(), GPJ_grass_to_osr(), and GPJ_osr_to_grass().

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(), and GPJ__get_datum_params().

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 377 of file proj/datum.c.

References buf, count, fclose(), fd, file, G_asprintf(), G_getl2(), G_gisbase(), G_store(), G_strcasecmp(), G_strip(), G_warning(), GPJ_free_datum(), GPJ_get_datum_by_name(), render::name, NULL, and sprintf().

Referenced by GPJ_ask_datum_params(), GPJ_get_default_datum_params_by_name(), and GPJ_osr_to_grass().

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 85 of file proj/datum.c.

References count, G_store(), GPJ_free_datum_transform(), GPJ_get_datum_transform_by_name(), NULL, and old.

Referenced by GPJ_osr_to_grass(), and pj_get_kv().

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 485 of file proj/datum.c.

References buf, count, DATUMTABLE, datum_list::dx, datum_list::dy, datum_list::dz, datum_list::ellps, fclose(), fd, file, G_getl2(), G_gisbase(), G_store(), G_strip(), G_warning(), datum_list::longname, datum_list::name, render::name, datum_list::next, NULL, read_datum_table(), and sprintf().

Referenced by GPJ_get_datum_by_name(), GPJ_osr_to_grass(), and read_datum_table().