shapeObj *msGEOSUnion(shapeObj *shape1, shapeObj *shape2)
{
#ifdef USE_GEOS
GEOSGeom g1, g2, g3;
if(!shape1 || !shape2)
return NULL;
if(!shape1->geometry) /* if no geometry for the shape then build one */
shape1->geometry = (GEOSGeom) msGEOSShape2Geometry(shape1);
g1 = (GEOSGeom) shape1->geometry;
if(!g1) return NULL;
if(!shape2->geometry) /* if no geometry for the shape then build one */
shape2->geometry = (GEOSGeom) msGEOSShape2Geometry(shape2);
g2 = (GEOSGeom) shape2->geometry;
if(!g2) return NULL;
g3 = GEOSUnion(g1, g2);
return msGEOSGeometry2Shape(g3);
#else
msSetError(MS_GEOSERR, "GEOS support is not available.", "msGEOSUnion()");
return NULL;
#endif
}
char *msudf_union(UDF_INIT *initid,UDF_ARGS *args, char *buf,
unsigned long *length, char *is_null, char *error)
{
char *result;
GEOSGeom geomFirst,geomSecond,geomResult;
DEBUG("msudf_union");
geomFirst = msudf_getGeometry((unsigned char *)args->args[0],args->lengths[0]);
if (geomFirst == NULL) {
strcpy(error,"Invalid geometry.");
*is_null = 1;
return 0;
}
geomSecond = msudf_getGeometry((unsigned char *)args->args[1],args->lengths[1]);
if (geomSecond == NULL) {
GEOSGeom_destroy(geomFirst);
strcpy(error,"Invalid geometry.");
*is_null = 1;
return 0;
}
geomResult = GEOSUnion(geomFirst,geomSecond);
if (geomResult!= NULL) {
GEOSSetSRID(geomResult,GEOSGetSRID(geomFirst));
result = msudf_returnGeometry(initid,length,geomResult);
GEOSGeom_destroy(geomFirst);
GEOSGeom_destroy(geomSecond);
GEOSGeom_destroy(geomResult);
return result;
} else {
GEOSGeom_destroy(geomFirst);
GEOSGeom_destroy(geomSecond);
*is_null = 1;
return NULL;
}
}
/* Initializes and uses GEOS internally */
static LWGEOM*
lwpoly_split_by_line(const LWPOLY* lwpoly_in, const LWLINE* blade_in)
{
LWCOLLECTION* out;
GEOSGeometry* g1;
GEOSGeometry* g2;
GEOSGeometry* g1_bounds;
GEOSGeometry* polygons;
const GEOSGeometry *vgeoms[1];
int i,n;
int hasZ = FLAGS_GET_Z(lwpoly_in->flags);
/* Possible outcomes:
*
* 1. The line does not split the polygon
* -> Return a collection with single element
* 2. The line does split the polygon
* -> Return a collection of all elements resulting from the split
*/
initGEOS(lwgeom_geos_error, lwgeom_geos_error);
g1 = LWGEOM2GEOS((LWGEOM*)lwpoly_in, 0);
if ( NULL == g1 )
{
lwerror("LWGEOM2GEOS: %s", lwgeom_geos_errmsg);
return NULL;
}
g1_bounds = GEOSBoundary(g1);
if ( NULL == g1_bounds )
{
GEOSGeom_destroy(g1);
lwerror("GEOSBoundary: %s", lwgeom_geos_errmsg);
return NULL;
}
g2 = LWGEOM2GEOS((LWGEOM*)blade_in, 0);
if ( NULL == g2 )
{
GEOSGeom_destroy(g1);
GEOSGeom_destroy(g1_bounds);
lwerror("LWGEOM2GEOS: %s", lwgeom_geos_errmsg);
return NULL;
}
vgeoms[0] = GEOSUnion(g1_bounds, g2);
if ( NULL == vgeoms[0] )
{
GEOSGeom_destroy(g1);
GEOSGeom_destroy(g2);
GEOSGeom_destroy(g1_bounds);
lwerror("GEOSUnion: %s", lwgeom_geos_errmsg);
return NULL;
}
polygons = GEOSPolygonize(vgeoms, 1);
if ( NULL == polygons )
{
GEOSGeom_destroy(g1);
GEOSGeom_destroy(g2);
GEOSGeom_destroy(g1_bounds);
GEOSGeom_destroy((GEOSGeometry*)vgeoms[0]);
lwerror("GEOSPolygonize: %s", lwgeom_geos_errmsg);
return NULL;
}
#if PARANOIA_LEVEL > 0
if ( GEOSGeomTypeId(polygons) != COLLECTIONTYPE )
{
GEOSGeom_destroy(g1);
GEOSGeom_destroy(g2);
GEOSGeom_destroy(g1_bounds);
GEOSGeom_destroy((GEOSGeometry*)vgeoms[0]);
GEOSGeom_destroy(polygons);
lwerror("%s [%s] Unexpected return from GEOSpolygonize", __FILE__, __LINE__);
return 0;
}
#endif
/* We should now have all polygons, just skip
* the ones which are in holes of the original
* geometries and return the rest in a collection
*/
n = GEOSGetNumGeometries(polygons);
out = lwcollection_construct_empty(COLLECTIONTYPE, lwpoly_in->srid,
hasZ, 0);
/* Allocate space for all polys */
out->geoms = lwrealloc(out->geoms, sizeof(LWGEOM*)*n);
assert(0 == out->ngeoms);
for (i=0; i<n; ++i)
{
GEOSGeometry* pos; /* point on surface */
const GEOSGeometry* p = GEOSGetGeometryN(polygons, i);
int contains;
pos = GEOSPointOnSurface(p);
if ( ! pos )
{
GEOSGeom_destroy(g1);
GEOSGeom_destroy(g2);
GEOSGeom_destroy(g1_bounds);
GEOSGeom_destroy((GEOSGeometry*)vgeoms[0]);
GEOSGeom_destroy(polygons);
lwerror("GEOSPointOnSurface: %s", lwgeom_geos_errmsg);
return NULL;
}
contains = GEOSContains(g1, pos);
if ( 2 == contains )
{
GEOSGeom_destroy(g1);
GEOSGeom_destroy(g2);
GEOSGeom_destroy(g1_bounds);
GEOSGeom_destroy((GEOSGeometry*)vgeoms[0]);
GEOSGeom_destroy(polygons);
GEOSGeom_destroy(pos);
lwerror("GEOSContains: %s", lwgeom_geos_errmsg);
return NULL;
}
GEOSGeom_destroy(pos);
if ( 0 == contains )
{
/* Original geometry doesn't contain
* a point in this ring, must be an hole
*/
continue;
}
out->geoms[out->ngeoms++] = GEOS2LWGEOM(p, hasZ);
}
GEOSGeom_destroy(g1);
GEOSGeom_destroy(g2);
GEOSGeom_destroy(g1_bounds);
GEOSGeom_destroy((GEOSGeometry*)vgeoms[0]);
GEOSGeom_destroy(polygons);
return (LWGEOM*)out;
}
LWGEOM*
lwgeom_union(const LWGEOM *geom1, const LWGEOM *geom2)
{
int is3d;
int srid;
GEOSGeometry *g1, *g2, *g3;
LWGEOM *result;
LWDEBUG(2, "in geomunion");
/* A.Union(empty) == A */
if ( lwgeom_is_empty(geom1) )
return lwgeom_clone(geom2);
/* B.Union(empty) == B */
if ( lwgeom_is_empty(geom2) )
return lwgeom_clone(geom1);
/* ensure srids are identical */
srid = (int)(geom1->srid);
error_if_srid_mismatch(srid, (int)(geom2->srid));
is3d = (FLAGS_GET_Z(geom1->flags) || FLAGS_GET_Z(geom2->flags)) ;
initGEOS(lwnotice, lwgeom_geos_error);
g1 = LWGEOM2GEOS(geom1);
if ( 0 == g1 ) /* exception thrown at construction */
{
lwerror("First argument geometry could not be converted to GEOS: %s", lwgeom_geos_errmsg);
return NULL;
}
g2 = LWGEOM2GEOS(geom2);
if ( 0 == g2 ) /* exception thrown at construction */
{
GEOSGeom_destroy(g1);
lwerror("Second argument geometry could not be converted to GEOS: %s", lwgeom_geos_errmsg);
return NULL;
}
LWDEBUGF(3, "g1=%s", GEOSGeomToWKT(g1));
LWDEBUGF(3, "g2=%s", GEOSGeomToWKT(g2));
g3 = GEOSUnion(g1,g2);
LWDEBUGF(3, "g3=%s", GEOSGeomToWKT(g3));
GEOSGeom_destroy(g1);
GEOSGeom_destroy(g2);
if (g3 == NULL)
{
lwerror("GEOSUnion: %s", lwgeom_geos_errmsg);
return NULL; /* never get here */
}
GEOSSetSRID(g3, srid);
result = GEOS2LWGEOM(g3, is3d);
GEOSGeom_destroy(g3);
if (result == NULL)
{
lwerror("Error performing union: GEOS2LWGEOM: %s",
lwgeom_geos_errmsg);
return NULL; /*never get here */
}
return result;
}
