lwgeom_from_geojson()

LWGEOM* lwgeom_from_geojson	(	const char *	geojson,
		char **	srs
	)

Create an LWGEOM object from a GeoJSON representation.

Parameters

geojson	the GeoJSON input
srs	output parameter. Will be set to a newly allocated string holding the spatial reference string, or NULL if no such parameter is found in input. If not null, the pointer must be freed with lwfree.

Definition at line 539 of file lwin_geojson.c.

References findMemberByName(), geojson_lwerror(), json_tokener_error_desc, LW_TRUE, lwalloc(), LWDEBUG, lwerror(), lwgeom_add_bbox(), lwgeom_force_2d(), lwgeom_free(), and parse_geojson().

Referenced by do_geojson_test(), and geom_from_geojson().

{
#ifndef HAVE_LIBJSON
        *srs = NULL;
        lwerror("You need JSON-C for lwgeom_from_geojson");
        return NULL;
#else /* HAVE_LIBJSON */

        /* size_t geojson_size = strlen(geojson); */

        LWGEOM *lwgeom;
        int hasz=LW_TRUE;
        json_tokener* jstok = NULL;
        json_object* poObj = NULL;
        json_object* poObjSrs = NULL;
        *srs = NULL;

        /* Begin to Parse json */
        jstok = json_tokener_new();
        poObj = json_tokener_parse_ex(jstok, geojson, -1);
        if( jstok->err != json_tokener_success)
        {
                char err[256];
                snprintf(err, 256, "%s (at offset %d)", json_tokener_error_desc(jstok->err), jstok->char_offset);
                json_tokener_free(jstok);
                json_object_put(poObj);
                geojson_lwerror(err, 1);
                return NULL;
        }
        json_tokener_free(jstok);

        poObjSrs = findMemberByName( poObj, "crs" );
        if (poObjSrs != NULL)
        {
                json_object* poObjSrsType = findMemberByName( poObjSrs, "type" );
                if (poObjSrsType != NULL)
                {
                        json_object* poObjSrsProps = findMemberByName( poObjSrs, "properties" );
                        if ( poObjSrsProps )
                        {
                                json_object* poNameURL = findMemberByName( poObjSrsProps, "name" );
                                if ( poNameURL )
                                {
                                        const char* pszName = json_object_get_string( poNameURL );
                                        if ( pszName )
                                        {
                                                *srs = lwalloc(strlen(pszName) + 1);
                                                strcpy(*srs, pszName);
                                        }
                                }
                        }
                }
        }

        lwgeom = parse_geojson(poObj, &hasz, 0);
        json_object_put(poObj);

        lwgeom_add_bbox(lwgeom);

        if (!hasz)
        {
                LWGEOM *tmp = lwgeom_force_2d(lwgeom);
                lwgeom_free(lwgeom);
                lwgeom = tmp;

                LWDEBUG(2, "geom_from_geojson called.");
        }

        return lwgeom;
#endif /* HAVE_LIBJSON } */
}

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