def simplify(self):
"""
Reduce the number of vertices in a polygon layer.
* Delete vertex if the angle with its adjacents is near of the straight
angle for less than 'straight_thr' degrees in all its parents.
* Delete vertex if the distance to the segment formed by its parents is
less than 'cath_thr' meters.
"""
if log.app_level <= logging.DEBUG:
debshp = DebugWriter("debug_simplify.shp", self)
killed = 0
to_change = {}
# Clean non corners
(parents_per_vertex,
geometries) = self.get_parents_per_vertex_and_geometries()
pbar = self.get_progressbar(_("Simplify"), len(parents_per_vertex))
for wkt, parents in parents_per_vertex.items():
point = Point(wkt)
# Test if this vertex is a 'corner' in any of its parent polygons
for fid in parents:
geom = geometries[fid]
(angle, is_acute, is_corner,
cath) = point.get_corner_context(geom)
debmsg = "angle=%.1f, is_acute=%s, is_corner=%s, cath=%.4f" % (
angle,
is_acute,
is_corner,
cath,
)
if is_corner:
break
msg = "Keep"
if not is_corner:
killed += 1 # delete the vertex from all its parents.
for fid in frozenset(parents):
g = QgsGeometry(geometries[fid])
(__, ndx, __, __, __) = g.closestVertex(point)
(ndxa, ndxb) = g.adjacentVertices(ndx)
v = g.vertexAt(ndx)
va = g.vertexAt(ndxa)
vb = g.vertexAt(ndxb)
invalid_ring = v == va or v == vb or va == vb
g.deleteVertex(ndx)
msg = "Refused"
if Geometry.is_valid(g) and not invalid_ring:
parents.remove(fid)
geometries[fid] = g
to_change[fid] = g
msg = "Deleted"
if log.app_level <= logging.DEBUG:
debshp.add_point(point, msg + " " + debmsg)
if len(to_change) > BUFFER_SIZE:
self.writer.changeGeometryValues(to_change)
to_change = {}
pbar.update()
pbar.close()
if len(to_change) > 0:
self.writer.changeGeometryValues(to_change)
if killed > 0:
log.debug(_("Simplified %d vertices in the '%s' layer"), killed,
self.name())
report.values["vertex_simplify_" + self.name()] = killed
def topology(self):
"""Add to nearest segments each vertex in a polygon layer."""
threshold = self.dist_thr # Distance threshold to create nodes
dup_thr = self.dup_thr
straight_thr = self.straight_thr
tp = 0
td = 0
if log.app_level <= logging.DEBUG:
debshp = DebugWriter("debug_topology.shp", self)
geometries = {
f.id(): QgsGeometry(f.geometry())
for f in self.getFeatures()
}
index = self.get_index()
to_change = {}
nodes = set()
pbar = self.get_progressbar(_("Topology"), len(geometries))
for (gid, geom) in geometries.items():
if geom.area() < config.min_area:
continue
for point in frozenset(Geometry.get_outer_vertices(geom)):
if point not in nodes:
area_of_candidates = Point(point).boundingBox(threshold)
fids = index.intersects(area_of_candidates)
for fid in fids:
g = QgsGeometry(geometries[fid])
(p, ndx, ndxa, ndxb, dist_v) = g.closestVertex(point)
(dist_s, closest,
vertex) = g.closestSegmentWithContext(point)[:3]
va = Point(g.vertexAt(ndxa))
vb = Point(g.vertexAt(ndxb))
note = ""
if dist_v == 0:
dist_a = va.sqrDist(point)
dist_b = vb.sqrDist(point)
if dist_a < dup_thr**2:
g.deleteVertex(ndxa)
note = "dupe refused by isGeosValid"
if Geometry.is_valid(g):
note = "Merge dup. %.10f %.5f,%.5f->%.5f,%.5f" % (
dist_a,
va.x(),
va.y(),
point.x(),
point.y(),
)
nodes.add(p)
nodes.add(va)
td += 1
if dist_b < dup_thr**2:
g.deleteVertex(ndxb)
note = "dupe refused by isGeosValid"
if Geometry.is_valid(g):
note = "Merge dup. %.10f %.5f,%.5f->%.5f,%.5f" % (
dist_b,
vb.x(),
vb.y(),
point.x(),
point.y(),
)
nodes.add(p)
nodes.add(vb)
td += 1
elif dist_v < dup_thr**2:
g.moveVertex(point.x(), point.y(), ndx)
note = "dupe refused by isGeosValid"
if Geometry.is_valid(g):
note = "Merge dup. %.10f %.5f,%.5f->%.5f,%.5f" % (
dist_v,
p.x(),
p.y(),
point.x(),
point.y(),
)
nodes.add(p)
td += 1
elif (dist_s < threshold**2 and closest != va
and closest != vb):
va = Point(g.vertexAt(vertex))
vb = Point(g.vertexAt(vertex - 1))
angle = abs(point.azimuth(va) - point.azimuth(vb))
note = "Topo refused by angle: %.2f" % angle
if abs(180 - angle) <= straight_thr:
note = "Topo refused by insertVertex"
if g.insertVertex(point.x(), point.y(),
vertex):
note = "Topo refused by isGeosValid"
if Geometry.is_valid(g):
note = "Add topo %.6f %.5f,%.5f" % (
dist_s,
point.x(),
point.y(),
)
tp += 1
if note.startswith("Merge") or note.startswith("Add"):
to_change[fid] = g
geometries[fid] = g
if note and log.app_level <= logging.DEBUG:
debshp.add_point(point, note)
if len(to_change) > BUFFER_SIZE:
self.writer.changeGeometryValues(to_change)
to_change = {}
pbar.update()
pbar.close()
if len(to_change) > 0:
self.writer.changeGeometryValues(to_change)
if td:
log.debug(_("Merged %d close vertices in the '%s' layer"), td,
self.name())
report.values["vertex_close_" + self.name()] = td
if tp:
log.debug(_("Created %d topological points in the '%s' layer"), tp,
self.name())
report.values["vertex_topo_" + self.name()] = tp
