def places_from_point(point, distance, place_type='city_block'):
"""
Download and create GeoDataFrame of 'place' polygons of the type 'place_type'.
use osmnx to download "place" polygons from a center point and distance to
edge of bounding box. Filter to retain minimal columns. Create new columns
recording perimeter in metres, area in hectares, and the perimeter per unit
area.
Parameters
----------
point : tuple
the (lat, lon) point to create the bounding box around
distance : int
how many meters the north, south, east, and west sides of the box should
each be from the point
Returns
-------
GeoDataFrame
"""
# use osmnx to download 'place' polygons
places = ox.footprints_from_point(point, distance, footprint_type="place")
# filter place polygons to retain only those of 'place_type'
places = places.loc[places['place'] == place_type]
# write the index into a column
places[place_type + '_id'] = places.index
# reindex the columns
places = places.reindex(columns=[place_type + '_id', 'place', 'geometry'])
# name the dataframe
places.gdf_name = place_type
return places
def test_multipolygon_footprint():
# 'point' is the location of known multipolygon building, relation id 1767022
point = (51.5276, -0.11)
gdf = ox.footprints_from_point(point=point, distance=20)
assert 1767022 in gdf.index, "relation 1767022 was not returned in the geodataframe"
assert gdf.loc[1767022][
'geometry'].type == 'MultiPolygon', "relation 1767022 is not a multipolygon"
def _fetch_from_remote(self, type_, cache_path):
if type_ == 'graph':
graph = ox.graph_from_point(self._center, self._distance, network_type=self._type)
self._store_graph_cache(graph, cache_path)
return graph
elif type_ == 'footprint':
gdf = ox.footprints_from_point(self._center, self._distance)
self._store_footprint_cache(gdf, cache_path)
return gdf
def test_footprints():
# download footprints and plot them
gdf = ox.footprints_from_place(place='Emeryville, California, USA')
gdf = ox.footprints_from_address(address='600 Montgomery St, San Francisco, California, USA', distance=300)
fig, ax = ox.plot_footprints(gdf)
# test multipolygon footprint
# point is the location of known multipolygon building, relation id 1767022
point = (51.5276, -0.11)
gdf = ox.footprints_from_point(point=point, distance=20, footprint_type='building')
assert 1767022 in gdf.index, "relation 1767022 was not returned in the geodataframe"
assert gdf.loc[1767022]['geometry'].type=='MultiPolygon', "relation 1767022 is not a multipolygon"
def test_footprints():
# download footprints and plot them
gdf = ox.footprints_from_place(place='Emeryville, California, USA')
gdf = ox.footprints_from_address(
address='600 Montgomery St, San Francisco, California, USA',
distance=300)
fig, ax = ox.plot_footprints(gdf)
# test multipolygon footprint
# point is the location of known multipolygon building, relation id 1767022
point = (51.5276, -0.11)
gdf = ox.footprints_from_point(point=point,
distance=20,
footprint_type='building')
assert 1767022 in gdf.index, "relation 1767022 was not returned in the geodataframe"
assert gdf.loc[1767022][
'geometry'].type == 'MultiPolygon', "relation 1767022 is not a multipolygon"
# -*- coding: utf-8 -*-
import os
import subprocess
import osmnx
# configure logging/caching
osmnx.config(log_console=True, use_cache=True)
# configure the image display
size = 256
# load buildings from about 1.5km² around UCL
point = (51.524498, -0.133874)
dist = 612
gdf = osmnx.footprints_from_point(point=point, dist=dist)
# preview image
gdf_proj = osmnx.projection.project_gdf(gdf, to_crs={'init': 'epsg:3857'})
gdf_proj = gdf_proj[gdf_proj.geometry.apply(
lambda g: g.geom_type != 'MultiPolygon')]
fig, ax = osmnx.plot_footprints(gdf_proj,
bgcolor='#333333',
color='w',
figsize=(4, 4),
save=True,
show=False,
close=True,
filename='test_buildings_preview',
dpi=600)