def test_polyline_round_trip(self):
test_polyline = ("gcneIpgxzRcDnBoBlEHzKjBbHlG`@`IkDxIi"
"KhKoMaLwTwHeIqHuAyGXeB~Ew@fFjAtIzExF")
points = convert.decode_polyline(test_polyline)
actual_polyline = convert.encode_polyline(points)
self.assertEqual(test_polyline, actual_polyline)
def get_path_from_h3(h3id, color="0xFF0000AA",
weight=1, fillcolor="0xFFB6C1BB"):
boundry = h3.h3_to_geo_boundary(h3id)
poly_lines = list(boundry)
poly_lines.append(boundry[0])
polyline_code = convert.encode_polyline(poly_lines)
return MAP_PATH.format(
color=color,
weight=weight,
fcolor=fillcolor,
poly_code=polyline_code
)
def generate_polyline(points):
return encode_polyline(points.values())
def divide_polyline(polyline_string_or_list=[""],
biggest_polyline_length=None,
include_interm_endpoints=True,
accumulate_distances=True):
"""
Divide up an encoded polyline or lists of polylines into lists of polylines
with specified length
:param polyline_string_or_list: encoded polyline string or list of strings
:type polyline_string_or_list: str or List(str)
:param biggest_polyline_length: cut-off length for polylines
:type biggest_polyline_length: numbers.Number
:param include_interm_endpoints: whether to include the first point in the next
:type include_interm_endpoints: bool
:param accumulate_distances: whether to accumulate distances along the lines
:type accumulate_distances: bool
:return: list of encoded polylines with specified length (except last)
:rtype: list of str
"""
import numpy as np
if isinstance(polyline_string_or_list, str):
polyline_string_or_list = [polyline_string_or_list]
if biggest_polyline_length is None:
biggest_polyline_length = np.inf
# generator over all coordinates in list
def next_coordinate(list_of_polyline_strings):
for _poly_string in list_of_polyline_strings:
coordinate_obj_list = con.decode_polyline(_poly_string)
for coord in coordinate_obj_list:
yield coord
all_coordinates = next_coordinate(polyline_string_or_list)
minimum_coord_distance = 0.5
result_polyline_lists = []
result_coordinate_distances = []
accumulated_distance = 0
previous_polylines_length = 0
current_distance_list = [accumulated_distance]
previous_coordinate = next(all_coordinates)
current_coordinate_list = [previous_coordinate]
for coordinate in all_coordinates:
reached_end_of_leg = False
while not reached_end_of_leg:
# ignore elevation
next_leg_length = distance_between_coordinates(
previous_coordinate, coordinate)
if next_leg_length < minimum_coord_distance: # ignore points too close
reached_end_of_leg = True # go to next coordinate
elif accumulated_distance + next_leg_length < biggest_polyline_length:
# can still add to polyline
current_coordinate_list.append(coordinate)
accumulated_distance += next_leg_length
current_distance_list.append(accumulated_distance)
previous_coordinate = coordinate
reached_end_of_leg = True
else: # split leg into two parts and start new polyline
required_leg_length = biggest_polyline_length - accumulated_distance
fraction_of_road_dist = required_leg_length / next_leg_length
# Note: this is an approximation for small distances. At 100km distance,
# this formula might give a result that is ~270 m off.
inbetween_coord_lat = (
previous_coordinate["lat"] + fraction_of_road_dist *
(coordinate["lat"] - previous_coordinate["lat"]))
inbetween_coord_lng = (
previous_coordinate["lng"] + fraction_of_road_dist *
(coordinate["lng"] - previous_coordinate["lng"]))
inbetween_coord = dict([("lat", inbetween_coord_lat),
("lng", inbetween_coord_lng)])
accumulated_distance += fraction_of_road_dist * next_leg_length
if include_interm_endpoints:
current_coordinate_list.append(inbetween_coord)
# should be == n * biggest_polyline_length
current_distance_list.append(accumulated_distance)
# add finished polyline to lists
result_polyline_lists.append(
con.encode_polyline(current_coordinate_list))
if accumulate_distances:
result_coordinate_distances.append(
list(
np.array(current_distance_list) +
previous_polylines_length))
previous_polylines_length += accumulated_distance
else:
result_coordinate_distances.append(current_distance_list)
current_coordinate_list = [inbetween_coord]
previous_coordinate = inbetween_coord
accumulated_distance = 0
current_distance_list = [accumulated_distance]
# add last lists
result_polyline_lists.append(con.encode_polyline(current_coordinate_list))
# previous_polylines_length only increases if accumulate_distances is set to True
result_coordinate_distances.append(
list(np.array(current_distance_list) + previous_polylines_length))
return result_polyline_lists, result_coordinate_distances