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 409 of file lwin_geojson.c.

{
#ifndef HAVE_LIBJSON
        *srs = NULL;
        lwerror("You need JSON-C for lwgeom_from_geojson");
        return NULL;
#else  /* HAVE_LIBJSON */
 
        /* Begin to Parse json */
        json_tokener *jstok = json_tokener_new();
        json_object *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);
                lwerror(err);
                return NULL;
        }
        json_tokener_free(jstok);
 
        *srs = NULL;
        json_object *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);
                                        }
                                }
                        }
                }
        }
 
        int hasz = LW_FALSE;
        LWGEOM *lwgeom = parse_geojson(poObj, &hasz);
        json_object_put(poObj);
        if (!lwgeom)
                return NULL;
 
        if (!hasz)
        {
                LWGEOM *tmp = lwgeom_force_2d(lwgeom);
                lwgeom_free(lwgeom);
                lwgeom = tmp;
        }
        lwgeom_add_bbox(lwgeom);
        return lwgeom;
#endif /* HAVE_LIBJSON */
}

References findMemberByName(), json_tokener_error_desc, LW_FALSE, lwalloc(), lwerror(), lwgeom_add_bbox(), lwgeom_force_2d(), lwgeom_free(), and parse_geojson().

Referenced by do_geojson_test(), and geom_from_geojson().

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