tspatial_transform_meos.c File Reference

Functions for transforming coordinates from one SRID to another one. More...

#include "geo/meos_transform.h"
#include <float.h>
#include <string.h>
#include <stdio.h>
#include <postgres.h>
#include <liblwgeom.h>
#include <meos.h>

Data Structures
struct	PjStrs
	Utility structure to get many potential string representations from spatial_ref_sys query. More...
struct	spatial_ref_sys_record
struct	struct_MEOSPROJSRSCache
	The proj4 cache holds a fixed number of reprojection entries. More...
struct	struct_PROJSRSCacheItem

Macros
#define	MAX_LENGTH_HEADER   1024
#define	MAX_LENGTH_SRS_RECORD   5120
#define	maxprojlen   512
#define	PROJ_BACKEND_HASH_SIZE   256
	PROJ 4 backend hash table initial hash size (since 16 is the default portal hash table size, and we would typically have 2 entries per portal then we shall use a default size of 256) More...
#define	PROJ_CACHE_ITEMS   128
#define	SPATIAL_REF_SYS_CSV   "/usr/local/lib/spatial_ref_sys.csv"
#define	spibufferlen   512

Typedefs
typedef struct struct_MEOSPROJSRSCache	MEOSPROJSRSCache
	The proj4 cache holds a fixed number of reprojection entries. More...
typedef struct struct_PROJSRSCacheItem	PROJSRSCacheItem

Functions
static LWPROJ *	AddToMEOSPROJSRSCache (MEOSPROJSRSCache *PROJCache, int32_t srid_from, int32_t srid_to)
	Add an entry to the PROJ SRS cache. More...
static void	DeleteFromMEOSPROJSRSCache (MEOSPROJSRSCache *PROJCache, uint32_t position)
	Remove an entry to the PROJ SRS cache. More...
MEOSPROJSRSCache *	GetMEOSPROJSRSCache ()
	Get the Proj cache entry from the global variable if one exists. More...
static LWPROJ *	GetProjectionFromPROJCache (MEOSPROJSRSCache *cache, int32_t srid_from, int32_t srid_to)
	Get a PROJ structure from the PROJ cache. More...
static PjStrs	GetProjStrings (int32_t srid)
	Given an SRID, return the corresponding proj strings (auth_name:auth_srid/srtext/proj4text) More...
static PjStrs	GetProjStringsSPI (int32_t srid)
	Return the PROJ strings of an SRID either from a CSV file spatial_ref_sys.csv (for MEOS) or from the PostGIS table spatial_ref_sys (for MobilityDB) More...
int	lwproj_lookup (int32_t srid_from, int32_t srid_to, LWPROJ **pj)
	Return 1 if the projection structure was read from the PROJ cache, return 0 otherwise. More...
void	meos_finalize_projsrs (void)
	Destroy all the malloc'ed PROJ objects stored in the PROJSRSCache. More...
static char *	pgstrs_get_entry (const PjStrs *strs, int n)
	Return the n-th string of a PROJ strings structure. More...
static int	pjstrs_has_entry (const PjStrs *strs)
	Return 1 if a PROJ strings structure has all its strings filled, return 0 otherwise. More...
static void	pjstrs_pfree (PjStrs *strs)
	Delete a PROJ strings structure. More...
static void	PROJSRSDestroyPJ (void *projection)
	Delete a PROJ structure referenced by a PostGIS projection structure. More...
int	spheroid_init_from_srid (int32_t srid, SPHEROID *s)
	Return 1 if the spheroid in the last argument was initialized from an SRID, return 0 otherwise. More...

Variables
MEOSPROJSRSCache *	MEOS_PROJ_CACHE = NULL

Detailed Description

Functions for transforming coordinates from one SRID to another one.

PostGIS manages a cache of information obtained from PROJ to speed up transformations (see file file libpgcommon/lw_transform.c). The functions in this file are derived from PostGIS functions by perforning memory allocation with malloc instead of using PostreSQL contexts.