/usr/lib/python3/dist-packages/mapbox_vector_tile/encoder.py is in python3-mapbox-vector-tile 0.5.0+ds-5.
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from numbers import Number
from past.builtins import long
from past.builtins import unicode
from past.builtins import xrange
from shapely.geometry.base import BaseGeometry
from shapely.geometry.multipolygon import MultiPolygon
from shapely.geometry.polygon import orient
from shapely.geometry.polygon import Polygon
from shapely.geometry.polygon import LinearRing
from shapely.ops import transform
from shapely.wkb import loads as load_wkb
from shapely.wkt import loads as load_wkt
import decimal
from .compat import PY3, vector_tile, apply_map
# tiles are padded by this number of pixels for the current zoom level
padding = 0
cmd_bits = 3
tolerance = 0
CMD_MOVE_TO = 1
CMD_LINE_TO = 2
CMD_SEG_END = 7
def on_invalid_geometry_raise(shape):
raise ValueError('Invalid geometry: %s' % shape.wkt)
def on_invalid_geometry_ignore(shape):
return None
def reverse_ring(shape):
assert shape.type == 'LinearRing'
return LinearRing(list(shape.coords)[::-1])
def reverse_polygon(shape):
assert shape.type == 'Polygon'
exterior = reverse_ring(shape.exterior)
interiors = [reverse_ring(r) for r in shape.interiors]
return Polygon(exterior, interiors)
def make_valid_polygon_flip(shape):
assert shape.type == 'Polygon'
# to handle cases where the area of the polygon is zero, we need to
# manually reverse the coords in the polygon, then buffer(0) it to make it
# valid in reverse, then reverse them again to get back to the original,
# intended orientation.
flipped = reverse_polygon(shape)
fixed = flipped.buffer(0)
if fixed.is_empty:
return None
else:
return reverse_polygon(fixed)
def area_bounds(shape):
if shape.is_empty:
return 0
minx, miny, maxx, maxy = shape.bounds
return (maxx - minx) * (maxy - miny)
def make_valid_polygon(shape):
prev_area = area_bounds(shape)
new_shape = shape.buffer(0)
assert new_shape.is_valid, \
'buffer(0) did not make geometry valid. old shape: %s' % shape.wkt
new_area = area_bounds(new_shape)
if new_area < 0.9 * prev_area:
alt_shape = make_valid_polygon_flip(shape)
if alt_shape:
new_shape = new_shape.union(alt_shape)
return new_shape
def make_valid_multipolygon(shape):
new_g = []
for g in shape.geoms:
if g.is_empty:
continue
valid_g = on_invalid_geometry_make_valid(g)
if valid_g.type == 'MultiPolygon':
new_g.extend(valid_g.geoms)
else:
new_g.append(valid_g)
return MultiPolygon(new_g)
def on_invalid_geometry_make_valid(shape):
if shape.is_empty:
return shape
elif shape.type == 'MultiPolygon':
shape = make_valid_multipolygon(shape)
elif shape.type == 'Polygon':
shape = make_valid_polygon(shape)
return shape
class VectorTile:
"""
"""
def __init__(self, extents, on_invalid_geometry=None,
max_geometry_validate_tries=5, round_fn=None):
self.tile = vector_tile.tile()
self.extents = extents
self.on_invalid_geometry = on_invalid_geometry
self.max_geometry_validate_tries = max_geometry_validate_tries
self.round_fn = round_fn
def _round(self, val):
# Prefer provided round function.
if self.round_fn:
return self.round_fn(val)
# round() has different behavior in python 2/3
# For consistency between 2 and 3 we use quantize, however
# it is slower than the built in round function.
d = decimal.Decimal(val)
rounded = d.quantize(1, rounding=decimal.ROUND_HALF_EVEN)
return float(rounded)
def addFeatures(self, features, layer_name='',
quantize_bounds=None, y_coord_down=False):
self.layer = self.tile.layers.add()
self.layer.name = layer_name
self.layer.version = 1
self.layer.extent = self.extents
self.key_idx = 0
self.val_idx = 0
self.seen_keys_idx = {}
self.seen_values_idx = {}
for feature in features:
# skip missing or empty geometries
geometry_spec = feature.get('geometry')
if geometry_spec is None:
continue
shape = self._load_geometry(geometry_spec)
if shape is None:
raise NotImplementedError(
'Can\'t do geometries that are not wkt, wkb, or shapely '
'geometries')
if shape.is_empty:
continue
if quantize_bounds:
shape = self.quantize(shape, quantize_bounds)
shape = self.enforce_winding_order(shape, y_coord_down)
if shape is not None and not shape.is_empty:
self.addFeature(feature, shape, y_coord_down)
def enforce_winding_order(self, shape, y_coord_down, n_try=1):
if shape.type == 'MultiPolygon':
# If we are a multipolygon, we need to ensure that the
# winding orders of the consituent polygons are
# correct. In particular, the winding order of the
# interior rings need to be the opposite of the
# exterior ones, and all interior rings need to follow
# the exterior one. This is how the end of one polygon
# and the beginning of another are signaled.
shape = self.enforce_multipolygon_winding_order(
shape, y_coord_down, n_try)
elif shape.type == 'Polygon':
# Ensure that polygons are also oriented with the
# appropriate winding order. Their exterior rings must
# have a clockwise order, which is translated into a
# clockwise order in MVT's tile-local coordinates with
# the Y axis in "screen" (i.e: +ve down) configuration.
# Note that while the Y axis flips, we also invert the
# Y coordinate to get the tile-local value, which means
# the clockwise orientation is unchanged.
shape = self.enforce_polygon_winding_order(
shape, y_coord_down, n_try)
# other shapes just get passed through
return shape
def quantize(self, shape, bounds):
minx, miny, maxx, maxy = bounds
def fn(x, y, z=None):
xfac = self.extents / (maxx - minx)
yfac = self.extents / (maxy - miny)
x = xfac * (x - minx)
y = yfac * (y - miny)
return self._round(x), self._round(y)
return transform(fn, shape)
def handle_shape_validity(self, shape, y_coord_down, n_try):
if shape.is_valid:
return shape
if n_try >= self.max_geometry_validate_tries:
# ensure that we don't recurse indefinitely with an
# invalid geometry handler that doesn't validate
# geometries
return None
if self.on_invalid_geometry:
shape = self.on_invalid_geometry(shape)
if shape is not None and not shape.is_empty:
# this means that we have a handler that might have
# altered the geometry. We'll run through the process
# again, but keep track of which attempt we are on to
# terminate the recursion.
shape = self.enforce_winding_order(
shape, y_coord_down, n_try + 1)
return shape
def enforce_multipolygon_winding_order(self, shape, y_coord_down, n_try):
assert shape.type == 'MultiPolygon'
parts = []
for part in shape.geoms:
part = self.enforce_polygon_winding_order(
part, y_coord_down, n_try)
if part is not None and not part.is_empty:
parts.append(part)
if not parts:
return None
if len(parts) == 1:
oriented_shape = parts[0]
else:
oriented_shape = MultiPolygon(parts)
oriented_shape = self.handle_shape_validity(
oriented_shape, y_coord_down, n_try)
return oriented_shape
def enforce_polygon_winding_order(self, shape, y_coord_down, n_try):
assert shape.type == 'Polygon'
def fn(point):
x, y = point
return self._round(x), self._round(y)
exterior = apply_map(fn, shape.exterior.coords)
rings = None
if len(shape.interiors) > 0:
rings = [apply_map(fn, ring.coords) for ring in shape.interiors]
sign = 1.0 if y_coord_down else -1.0
oriented_shape = orient(Polygon(exterior, rings), sign=sign)
oriented_shape = self.handle_shape_validity(
oriented_shape, y_coord_down, n_try)
return oriented_shape
def _load_geometry(self, geometry_spec):
if isinstance(geometry_spec, BaseGeometry):
return geometry_spec
try:
return load_wkb(geometry_spec)
except:
try:
return load_wkt(geometry_spec)
except:
return None
def addFeature(self, feature, shape, y_coord_down):
f = self.layer.features.add()
fid = feature.get('id')
if fid is not None:
if isinstance(fid, Number) and fid >= 0:
f.id = fid
# properties
properties = feature.get('properties')
if properties is not None:
self._handle_attr(self.layer, f, properties)
f.type = self._get_feature_type(shape)
self._geo_encode(f, shape, y_coord_down)
def _get_feature_type(self, shape):
if shape.type == 'Point' or shape.type == 'MultiPoint':
return self.tile.Point
elif shape.type == 'LineString' or shape.type == 'MultiLineString':
return self.tile.LineString
elif shape.type == 'Polygon' or shape.type == 'MultiPolygon':
return self.tile.Polygon
elif shape.type == 'GeometryCollection':
raise ValueError('Encoding geometry collections not supported')
else:
raise ValueError('Cannot encode unknown geometry type: %s' %
shape.type)
def _encode_cmd_length(self, cmd, length):
return (length << cmd_bits) | (cmd & ((1 << cmd_bits) - 1))
def _chunker(self, seq, size):
return [seq[pos:pos + size] for pos in xrange(0, len(seq), size)]
def _can_handle_key(self, k):
return isinstance(k, (str, unicode))
def _can_handle_val(self, v):
if isinstance(v, (str, unicode)):
return True
elif isinstance(v, bool):
return True
elif isinstance(v, (int, long)):
return True
elif isinstance(v, float):
return True
return False
def _can_handle_attr(self, k, v):
return self._can_handle_key(k) and \
self._can_handle_val(v)
def _handle_attr(self, layer, feature, props):
for k, v in props.items():
if self._can_handle_attr(k, v):
if not PY3 and isinstance(k, str):
k = k.decode('utf-8')
if k not in self.seen_keys_idx:
layer.keys.append(k)
self.seen_keys_idx[k] = self.key_idx
self.key_idx += 1
feature.tags.append(self.seen_keys_idx[k])
if v not in self.seen_values_idx:
self.seen_values_idx[v] = self.val_idx
self.val_idx += 1
val = layer.values.add()
if isinstance(v, bool):
val.bool_value = v
elif isinstance(v, str):
if PY3:
val.string_value = v
else:
val.string_value = unicode(v, 'utf-8')
elif isinstance(v, unicode):
val.string_value = v
elif isinstance(v, (int, long)):
val.int_value = v
elif isinstance(v, float):
val.double_value = v
feature.tags.append(self.seen_values_idx[v])
def _handle_skipped_last(self, f, skipped_index, cur_x, cur_y, x_, y_):
last_x = f.geometry[skipped_index - 2]
last_y = f.geometry[skipped_index - 1]
last_dx = ((last_x >> 1) ^ (-(last_x & 1)))
last_dy = ((last_y >> 1) ^ (-(last_y & 1)))
dx = cur_x - x_ + last_dx
dy = cur_y - y_ + last_dy
x_ = cur_x
y_ = cur_y
f.geometry.__setitem__(skipped_index - 2, ((dx << 1) ^ (dx >> 31)))
f.geometry.__setitem__(skipped_index - 1, ((dy << 1) ^ (dy >> 31)))
def _parseGeometry(self, shape):
coordinates = []
lineType = "line"
polygonType = "polygon"
def _get_arc_obj(arc, type):
cmd = CMD_MOVE_TO
length = len(arc.coords)
for i, (x, y) in enumerate(arc.coords):
if i == 0:
cmd = CMD_MOVE_TO
elif i == length - 1 and type == polygonType:
cmd = CMD_SEG_END
else:
cmd = CMD_LINE_TO
coordinates.append((x, y, cmd))
if shape.type == 'GeometryCollection':
# do nothing
coordinates = []
elif shape.type == 'Point':
coordinates.append((shape.x, shape.y, CMD_MOVE_TO))
elif shape.type == 'LineString':
_get_arc_obj(shape, lineType)
elif shape.type == 'Polygon':
rings = [shape.exterior] + list(shape.interiors)
for ring in rings:
_get_arc_obj(ring, polygonType)
elif shape.type == 'MultiPoint':
coordinates += [(point.x, point.y, CMD_MOVE_TO)
for point in shape.geoms]
elif shape.type == 'MultiLineString':
for arc in shape.geoms:
_get_arc_obj(arc, lineType)
elif shape.type == 'MultiPolygon':
for polygon in shape.geoms:
rings = [polygon.exterior] + list(polygon.interiors)
for ring in rings:
_get_arc_obj(ring, polygonType)
else:
raise NotImplementedError("Can't do %s geometries" % shape.type)
return coordinates
def _geo_encode(self, f, shape, y_coord_down):
x_, y_ = 0, 0
cmd = -1
cmd_idx = -1
vtx_cmd = -1
prev_cmd = -1
skipped_index = -1
skipped_last = False
cur_x = 0
cur_y = 0
it = 0
length = 0
coordinates = self._parseGeometry(shape)
while it < len(coordinates):
x, y, vtx_cmd = coordinates[it]
if vtx_cmd != cmd:
if cmd_idx >= 0:
f.geometry[cmd_idx] = self._encode_cmd_length(cmd, length)
cmd = vtx_cmd
length = 0
cmd_idx = len(f.geometry)
f.geometry.append(0) # placeholder added in first pass
if (vtx_cmd == CMD_MOVE_TO or vtx_cmd == CMD_LINE_TO):
if cmd == CMD_MOVE_TO and skipped_last and skipped_index > 1:
self._handle_skipped_last(
f, skipped_index, cur_x, cur_y, x_, y_)
# ensure that floating point values don't get truncated
if isinstance(x, float):
x = self._round(x)
if isinstance(y, float):
y = self._round(y)
x = int(x)
y = int(y)
if not y_coord_down:
y = self.extents - y
# Compute delta to the previous coordinate.
cur_x = int(x)
cur_y = int(y)
dx = cur_x - x_
dy = cur_y - y_
sharp_turn_ahead = False
if (it + 2 <= len(coordinates)):
next_x, next_y, next_cmd = coordinates[it + 1]
if next_cmd == CMD_LINE_TO:
next_dx = fabs(cur_x - int(next_x))
next_dy = fabs(cur_y - int(next_y))
if ((next_dx == 0 and next_dy >= tolerance) or
(next_dy == 0 and next_dx >= tolerance)):
sharp_turn_ahead = True
# Keep all move_to commands, but omit other movements
# that are not >= the tolerance threshold and should
# be considered no-ops.
# NOTE: length == 0 indicates the command has changed and will
# preserve any non duplicate move_to or line_to
if (length == 0 or sharp_turn_ahead or
fabs(dx) >= tolerance or fabs(dy) >= tolerance):
# Manual zigzag encoding.
f.geometry.append((dx << 1) ^ (dx >> 31))
f.geometry.append((dy << 1) ^ (dy >> 31))
x_ = cur_x
y_ = cur_y
skipped_last = False
length = length + 1
else:
skipped_last = True
skipped_index = len(f.geometry)
elif vtx_cmd == CMD_SEG_END:
if prev_cmd != CMD_SEG_END:
length = length + 1
else:
raise Exception("Unknown command type: '%s'" % vtx_cmd)
it = it + 1
prev_cmd = cmd
# at least one vertex + cmd/length
if skipped_last and skipped_index > 1:
# if we skipped previous vertex we just update it to the
# last one here.
self._handle_skipped_last(f, skipped_index, cur_x, cur_y, x_, y_)
# Update the last length/command value.
if cmd_idx >= 0:
f.geometry[cmd_idx] = self._encode_cmd_length(cmd, length)
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