char *msudf_boundary(UDF_INIT *initid,UDF_ARGS *args, char *buf,
unsigned long *length, char *is_null, char *error)
{
char *result;
GEOSGeom geom1,geom2;
DEBUG("msudf_boundary");
geom1 = msudf_getGeometry((unsigned char *)args->args[0],args->lengths[0]);
if (geom1 == NULL) {
strcpy(error,"Invalid geometry.");
*is_null = 1;
return NULL;
}
geom2 = GEOSBoundary(geom1);
if (geom2 != NULL) {
GEOSSetSRID(geom2,GEOSGetSRID(geom1));
result = msudf_returnGeometry(initid,length,geom2);
GEOSGeom_destroy(geom1);
GEOSGeom_destroy(geom2);
return result;
} else {
GEOSGeom_destroy(geom1);
*is_null = 1;
return NULL;
}
}
shapeObj *msGEOSBoundary(shapeObj *shape)
{
#ifdef USE_GEOS
GEOSGeom g1, g2;
if(!shape) return NULL;
if(!shape->geometry) /* if no geometry for the shape then build one */
shape->geometry = (GEOSGeom) msGEOSShape2Geometry(shape);
g1 = (GEOSGeom) shape->geometry;
if(!g1) return NULL;
g2 = GEOSBoundary(g1);
return msGEOSGeometry2Shape(g2);
#else
msSetError(MS_GEOSERR, "GEOS support is not available.", "msGEOSBoundary()");
return NULL;
#endif
}
/* Initializes and uses GEOS internally */
static LWGEOM*
lwline_split_by_line(const LWLINE* lwline_in, const LWGEOM* blade_in)
{
LWGEOM** components;
LWGEOM* diff;
LWCOLLECTION* out;
GEOSGeometry* gdiff; /* difference */
GEOSGeometry* g1;
GEOSGeometry* g2;
int ret;
/* ASSERT blade_in is LINE or MULTILINE */
assert (blade_in->type == LINETYPE ||
blade_in->type == MULTILINETYPE ||
blade_in->type == POLYGONTYPE ||
blade_in->type == MULTIPOLYGONTYPE );
/* Possible outcomes:
*
* 1. The lines do not cross or overlap
* -> Return a collection with single element
* 2. The lines cross
* -> Return a collection of all elements resulting from the split
*/
initGEOS(lwgeom_geos_error, lwgeom_geos_error);
g1 = LWGEOM2GEOS((LWGEOM*)lwline_in, 0);
if ( ! g1 )
{
lwerror("LWGEOM2GEOS: %s", lwgeom_geos_errmsg);
return NULL;
}
g2 = LWGEOM2GEOS(blade_in, 0);
if ( ! g2 )
{
GEOSGeom_destroy(g1);
lwerror("LWGEOM2GEOS: %s", lwgeom_geos_errmsg);
return NULL;
}
/* If blade is a polygon, pick its boundary */
if ( blade_in->type == POLYGONTYPE || blade_in->type == MULTIPOLYGONTYPE )
{
gdiff = GEOSBoundary(g2);
GEOSGeom_destroy(g2);
if ( ! gdiff )
{
GEOSGeom_destroy(g1);
lwerror("GEOSBoundary: %s", lwgeom_geos_errmsg);
return NULL;
}
g2 = gdiff; gdiff = NULL;
}
/* If interior intersecton is linear we can't split */
ret = GEOSRelatePattern(g1, g2, "1********");
if ( 2 == ret )
{
lwerror("GEOSRelatePattern: %s", lwgeom_geos_errmsg);
GEOSGeom_destroy(g1);
GEOSGeom_destroy(g2);
return NULL;
}
if ( ret )
{
GEOSGeom_destroy(g1);
GEOSGeom_destroy(g2);
lwerror("Splitter line has linear intersection with input");
return NULL;
}
gdiff = GEOSDifference(g1,g2);
GEOSGeom_destroy(g1);
GEOSGeom_destroy(g2);
if (gdiff == NULL)
{
lwerror("GEOSDifference: %s", lwgeom_geos_errmsg);
return NULL;
}
diff = GEOS2LWGEOM(gdiff, FLAGS_GET_Z(lwline_in->flags));
GEOSGeom_destroy(gdiff);
if (NULL == diff)
{
lwerror("GEOS2LWGEOM: %s", lwgeom_geos_errmsg);
return NULL;
}
out = lwgeom_as_lwcollection(diff);
if ( ! out )
{
components = lwalloc(sizeof(LWGEOM*)*1);
components[0] = diff;
out = lwcollection_construct(COLLECTIONTYPE, lwline_in->srid,
NULL, 1, components);
}
else
{
/* Set SRID */
lwgeom_set_srid((LWGEOM*)out, lwline_in->srid);
/* Force collection type */
out->type = COLLECTIONTYPE;
}
return (LWGEOM*)out;
}
/* 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;
}
