GRASS GIS 7 Programmer's Manual  7.5.svn(2017)-r71759
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proj/datum.c File Reference

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_listGPJ_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>

(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 proj/datum.c.

Function Documentation

void free_datum_list ( struct datum_list *  dstruct)

Free the memory used by a datum_list linked list structure.

Parameters
dstructdatum_list struct to be freed

Definition at line 417 of file proj/datum.c.

References G_free(), NULL, and old.

Referenced by GPJ_get_datum_by_name(), and GPJ_osr_to_grass().

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
projinfoSet of key_value pairs containing projection information in PROJ_INFO file format
datumnamePointer 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.
paramsPointer 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(), G_warning(), getenv(), HOST_DIRSEP, and NULL.

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

void GPJ_free_datum ( struct gpj_datum dstruct)

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

Parameters
dstructgpj_datum struct to be freed

Definition at line 403 of file proj/datum.c.

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

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)
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
nameString containing datum name to look up
dstructgpj_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 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, 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
namePointer 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.
paramsPointer 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
inputnameString 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 _, gpj_datum_transform_list::comment, count, gpj_datum_transform_list::count, DATUMTRANSFORMTABLE, gpj_datum::dx, gpj_datum::dy, gpj_datum::dz, fclose(), fd, file, G_asprintf(), G_getl2(), G_gisbase(), G_store(), G_strcasecmp(), G_strip(), G_warning(), GPATH_MAX, GPJ_free_datum(), GPJ_get_datum_by_name(), name, gpj_datum_transform_list::next, NULL, gpj_datum_transform_list::params, and gpj_datum_transform_list::where_used.

Referenced by 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
nameString containing GRASS datum name for which default parameters are to be retrieved
paramsPointer 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(), list, gpj_datum_transform_list::next, NULL, old, and gpj_datum_transform_list::params.

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 345 of file proj/datum.c.

References _, count, DATUMTABLE, fclose(), fd, file, G_getl2(), G_gisbase(), G_store(), G_strip(), G_warning(), GPATH_MAX, name, and NULL.

Referenced by GPJ_get_datum_by_name(), and GPJ_osr_to_grass().