Function msGEOSIntersects

mapgeos.c:1031–1077

** Does shape1 intersect shape2, returns MS_TRUE/MS_FALSE or -1 for an error. */

** Does shape1 intersect shape2, returns MS_TRUE/MS_FALSE or -1 for an error.
*/
int msGEOSIntersects(shapeObj *shape1, shapeObj *shape2)
{
#ifdef USE_GEOS
  GEOSGeom g1, g2;
  int result;

  if(!shape1 || !shape2)
    return -1;

  if(!shape1->geometry) /* if no geometry for shape1 then build one */
    shape1->geometry = (GEOSGeom) msGEOSShape2Geometry(shape1);
  g1 = (GEOSGeom) shape1->geometry;
  if(!g1) return -1;

  if(!shape2->geometry) /* if no geometry for shape2 then build one */
    shape2->geometry = (GEOSGeom) msGEOSShape2Geometry(shape2);
  g2 = (GEOSGeom) shape2->geometry;
  if(!g2) return -1;

  result = GEOSIntersects(g1, g2);  
  return ((result==2) ? -1 : result);
#else
  if(!shape1 || !shape2)
    return -1;

  switch(shape1->type) { /* todo: deal with point shapes */
  case(MS_SHAPE_LINE):
    switch(shape2->type) {
    case(MS_SHAPE_LINE):
      return msIntersectPolylines(shape1, shape2);
    case(MS_SHAPE_POLYGON):
      return msIntersectPolylinePolygon(shape1, shape2);
    }
    break;
  case(MS_SHAPE_POLYGON):
    switch(shape2->type) {
    case(MS_SHAPE_LINE):
      return msIntersectPolylinePolygon(shape2, shape1);
    case(MS_SHAPE_POLYGON):
      return msIntersectPolygons(shape1, shape2);
    }
    break;
  }

  return -1;
#endif
}

/*
** Does shape1 touch shape2, returns MS_TRUE/MS_FALSE or -1 for an error.