/**
* For an #LWGEOM, returns 0 for points, 1 for lines,
* 2 for polygons, 3 for volume, and the max dimension
* of a collection.
*/
int lwgeom_dimension(const LWGEOM *geom)
{
/* Null? Zero. */
if( ! geom ) return -1;
LWDEBUGF(4, "lwgeom_dimension got type %s",
lwtype_name(geom->type));
/* Empty? Zero. */
/* if( lwgeom_is_empty(geom) ) return 0; */
switch (geom->type)
{
case POINTTYPE:
case MULTIPOINTTYPE:
return 0;
case CIRCSTRINGTYPE:
case LINETYPE:
case COMPOUNDTYPE:
case MULTICURVETYPE:
case MULTILINETYPE:
return 1;
case TRIANGLETYPE:
case POLYGONTYPE:
case CURVEPOLYTYPE:
case MULTISURFACETYPE:
case MULTIPOLYGONTYPE:
case TINTYPE:
return 2;
case POLYHEDRALSURFACETYPE:
{
/* A closed polyhedral surface contains a volume. */
int closed = lwpsurface_is_closed((LWPSURFACE*)geom);
return ( closed ? 3 : 2 );
}
case COLLECTIONTYPE:
{
int maxdim = 0, i;
LWCOLLECTION *col = (LWCOLLECTION*)geom;
for( i = 0; i < col->ngeoms; i++ )
{
int dim = lwgeom_dimension(col->geoms[i]);
maxdim = ( dim > maxdim ? dim : maxdim );
}
return maxdim;
}
default:
lwerror("lwgeom_dimension: unsupported input geometry type: %s",
lwtype_name(geom->type));
}
return -1;
}
Datum LWGEOM_dimension(PG_FUNCTION_ARGS)
{
GSERIALIZED *geom = (GSERIALIZED *)PG_DETOAST_DATUM(PG_GETARG_DATUM(0));
LWGEOM *lwgeom = lwgeom_from_gserialized(geom);
int dimension = -1;
dimension = lwgeom_dimension(lwgeom);
lwgeom_free(lwgeom);
PG_FREE_IF_COPY(geom, 0);
if ( dimension < 0 )
{
elog(NOTICE, "Could not compute geometry dimensions");
PG_RETURN_NULL();
}
PG_RETURN_INT32(dimension);
}
LWGEOM*
lwgeom_node(const LWGEOM* lwgeom_in)
{
#if POSTGIS_GEOS_VERSION < 33
lwerror("The GEOS version this postgis binary "
"was compiled against (%d) doesn't support "
"'GEOSUnaryUnion' function (3.3.0+ required)",
POSTGIS_GEOS_VERSION);
return NULL;
#else /* POSTGIS_GEOS_VERSION >= 33 */
GEOSGeometry *g1, *gu, *gm;
LWGEOM *ep, *lines;
LWCOLLECTION *col, *tc;
int pn, ln, np, nl;
if ( lwgeom_dimension(lwgeom_in) != 1 ) {
lwerror("Noding geometries of dimension != 1 is unsupported");
return NULL;
}
initGEOS(lwgeom_geos_error, lwgeom_geos_error);
g1 = LWGEOM2GEOS(lwgeom_in);
if ( ! g1 ) {
lwerror("LWGEOM2GEOS: %s", lwgeom_geos_errmsg);
return NULL;
}
ep = lwgeom_extract_unique_endpoints(lwgeom_in);
if ( ! ep ) {
GEOSGeom_destroy(g1);
lwerror("Error extracting unique endpoints from input");
return NULL;
}
/* Unary union input to fully node */
gu = GEOSUnaryUnion(g1);
GEOSGeom_destroy(g1);
if ( ! gu ) {
lwgeom_free(ep);
lwerror("GEOSUnaryUnion: %s", lwgeom_geos_errmsg);
return NULL;
}
/* Linemerge (in case of overlaps) */
gm = GEOSLineMerge(gu);
GEOSGeom_destroy(gu);
if ( ! gm ) {
lwgeom_free(ep);
lwerror("GEOSLineMerge: %s", lwgeom_geos_errmsg);
return NULL;
}
lines = GEOS2LWGEOM(gm, FLAGS_GET_Z(lwgeom_in->flags));
GEOSGeom_destroy(gm);
if ( ! lines ) {
lwgeom_free(ep);
lwerror("Error during GEOS2LWGEOM");
return NULL;
}
/*
* Reintroduce endpoints from input, using split-line-by-point.
* Note that by now we can be sure that each point splits at
* most _one_ segment as any point shared by multiple segments
* would already be a node. Also we can be sure that any of
* the segments endpoints won't split any other segment.
* We can use the above 2 assertions to early exit the loop.
*/
col = lwcollection_construct_empty(MULTILINETYPE, lwgeom_in->srid,
FLAGS_GET_Z(lwgeom_in->flags),
FLAGS_GET_M(lwgeom_in->flags));
np = lwgeom_ngeoms(ep);
for (pn=0; pn<np; ++pn) { /* for each point */
const LWPOINT* p = (LWPOINT*)lwgeom_subgeom(ep, pn);
nl = lwgeom_ngeoms(lines);
for (ln=0; ln<nl; ++ln) { /* for each line */
const LWLINE* l = (LWLINE*)lwgeom_subgeom(lines, ln);
int s = lwline_split_by_point_to(l, p, (LWMLINE*)col);
if ( ! s ) continue; /* not on this line */
if ( s == 1 ) {
/* found on this line, but not splitting it */
break;
}
/* splits this line */
/* replace this line with the two splits */
if ( lwgeom_is_collection(lines) ) {
tc = (LWCOLLECTION*)lines;
lwcollection_reserve(tc, nl + 1);
while (nl > ln+1) {
tc->geoms[nl] = tc->geoms[nl-1];
--nl;
}
lwgeom_free(tc->geoms[ln]);
tc->geoms[ln] = col->geoms[0];
tc->geoms[ln+1] = col->geoms[1];
tc->ngeoms++;
} else {
lwgeom_free(lines);
/* transfer ownership rather than cloning */
lines = (LWGEOM*)lwcollection_clone_deep(col);
assert(col->ngeoms == 2);
lwgeom_free(col->geoms[0]);
lwgeom_free(col->geoms[1]);
}
/* reset the vector */
assert(col->ngeoms == 2);
col->ngeoms = 0;
break;
}
}
lwgeom_free(ep);
lwcollection_free(col);
lines->srid = lwgeom_in->srid;
return (LWGEOM*)lines;
#endif /* POSTGIS_GEOS_VERSION >= 33 */
}