module datainc.data_geo_streets

Short summary

module ensae_projects.datainc.data_geo_streets

Data related to a challenge, streets in Seattle

source on GitHub

Functions

function	truncated documentation
_complete_subset_streets	Extends a set of edges to have less extermities into the graph composed by the sets of edges.
_enumerate_close	Enumerates close streets from a starting point.
build_streets_vertices	Returns vertices and edges based on the subset of edges.
connect_streets	Tells if streets st1, st2 are connected.
folium_html_street_map	Returns a folium map which represents the streets.
get_fields_description	Retrieves a dataframe which describes the meaning of the metadata.
get_seattle_streets	Retrieves processed data from Seattle Streets. …
plot_streets_network	Plots the network based on cartopy.
plot_streets_network_projection	Returns the default projection for plot_streets_network(). See projection. …
seattle_streets_set_level	Returns a graph of streets.
seattle_streets_set_level2	Returns a small graph of streets.
seattle_streets_set_level3	Returns a small graph of streets.
seattle_streets_set_small	Returns a small graph of streets.
shapely_records	Uses pyshp to return shapes and records from shapefiles.

Documentation

Data related to a challenge, streets in Seattle

source on GitHub

ensae_projects.datainc.data_geo_streets._complete_subset_streets(edges, shapes)

Extends a set of edges to have less extermities into the graph composed by the sets of edges.

Parameters:

• edges – list of indices in shapes

• shapes – streets

Returns:

added edges (indices)

source on GitHub

ensae_projects.datainc.data_geo_streets._enumerate_close(lon, lat, shapes, th=None)

Enumerates close streets from a starting point.

Parameters:

• lon – longitude

• lat – latitude

• shapes – list of streets

• th – threshold or None for all

Returns:

iterator on tuple(distance, i)

source on GitHub

ensae_projects.datainc.data_geo_streets.build_streets_vertices(edges, shapes)

Returns vertices and edges based on the subset of edges.

Parameters:

• edges – indexes

• shapes – streets

Returns:

vertices, edges

vertices is a list of points. edges is a list of tuple(a, b) where a, b are indices refering to the array of vertices

source on GitHub

ensae_projects.datainc.data_geo_streets.connect_streets(st1, st2)

Tells if streets st1, st2 are connected.

Parameters:

• st1 – street 1

• st2 – street 2

Returns:

tuple or tuple (0 or 1, 0 or 1)

Each tuple means:

• 0 or 1 mean first or last extremity or the first street

• 0 or 1 mean first or last extremity or the second street

((0, 1),) means the first point of the first street is connected to the second extremity of the second street.

source on GitHub

ensae_projects.datainc.data_geo_streets.folium_html_street_map(subset, shapes, html_width=None, html_height=None, color_vertices=None, **kwargs)

Returns a folium map which represents the streets.

Parameters:

• subset – list of streets index

• shapes – list of shapes

• kwargs – extra parameters for Map

• html_width – sent to function folium_html_map

• html_height –

  sent to function folium_html_map

• color_vertices – see below

Returns:

see function folium_html_map

if color_vertices is equal to ‘odd’, the function computes the degree of each vertex and choose a different color for odd (yellow) and even degrees (black).

source on GitHub

ensae_projects.datainc.data_geo_streets.get_fields_description()

Retrieves a dataframe which describes the meaning of the metadata.

Returns:

dataframe

source on GitHub

ensae_projects.datainc.data_geo_streets.get_seattle_streets(filename=None, folder='.')

Retrieves processed data from Seattle Streets.

Parameters:

• filename – local filename

• folder – temporary folder where to download files

Returns:

shapes, records

The function returns a filename.

source on GitHub

ensae_projects.datainc.data_geo_streets.plot_streets_network(edges_index, edges, vertices, shapes, order=None, color_vertices=None, color_edges=None, ax=None, **kwargs)

Plots the network based on cartopy.

Parameters:

• edges_index – index of the edges in shapes

• edges – list of tuple(v1, v2) in array of vertices

• vertices – list of vertices coordinates

• shapes – streets

• order – list of edges composing a path (eulerian path)

• color_vertices – dictionary { vertex_index: color }, changes the color associated to each vertex (black by default)

• color_edges – dictionary { edges_index: color }, changes the color associated to each edge (black by default)

• ax – axis or None

• kwargs – parameter used to create the plot is ax is None

Returns:

ax

kwargs may contain parameters: color_v, color_e, size_v, size_e, size_c, size_et.

If order is not None, the function replaces the edge index by its position in this array.

if color_vertices is equal to ‘odd’, the function computes the degree of each vertex and choose a different color for odd (yellow) and even degrees (black). If ax is predefined, it should contain the parameter:

import cartopy.crs as ccrs
import matplotlib.pyplot as plt
from ensae_projects.datainc.data_geo_streets import plot_streets_network_projection
fig = plt.figure(figsize=(7,7))
ax = fig.add_subplot(1, 1, 1, projection=plot_streets_network_projection())

The default projection is given by plot_streets_network_projection. https://scitools.org.uk/cartopy/docs/v0.15/examples/hurricane_katrina.html

source on GitHub

ensae_projects.datainc.data_geo_streets.plot_streets_network_projection(central_longitude=0.0, min_latitude=-80.0, max_latitude=84.0, globe=None, latitude_true_scale=0.0)

Returns the default projection for plot_streets_network. See projection.

source on GitHub

ensae_projects.datainc.data_geo_streets.seattle_streets_set_level(shapes, records, pos=(-122.3521425, 47.6219965), size=120)

Returns a graph of streets.

Parameters:

• shapes – list of streets

• records – description of each street

• pos – center of the graphs

• size – number of elements

Returns:

indices of edges, edges, vertices, distances

The function uses the fields SEGMENT_TY to filter out train, rail ways.

source on GitHub

ensae_projects.datainc.data_geo_streets.seattle_streets_set_level2(shapes, records, size=120)

Returns a small graph of streets.

Parameters:

• shapes – list of streets

• records – description of each street

• size – number of elements

Returns:

indices of edges, edges, vertices, distances

source on GitHub

ensae_projects.datainc.data_geo_streets.seattle_streets_set_level3(shapes, records, size=1200)

Returns a small graph of streets.

Parameters:

• shapes – list of streets

• records – description of each street

• size – number of elements

Returns:

indices of edges, edges, vertices, distances

source on GitHub

ensae_projects.datainc.data_geo_streets.seattle_streets_set_small(shapes, records, size=20)

Returns a small graph of streets.

Parameters:

• shapes – list of streets

• records – description of each street

• size – number of elements

Returns:

indices of edges, edges, vertices, distances

source on GitHub

ensae_projects.datainc.data_geo_streets.shapely_records(filename, **kwargs)

Uses pyshp to return shapes and records from shapefiles.

Parameters:

• filename – filename

• kwargs – addition parameter for the shapefile reader, useful options car encoding and encodingErrors

Returns:

shapes, records, fields

Fields in shapefiles

The following codes is usually used to retrieve shapefiles:

rshp = shapefile.Reader(filename)
shapes = rshp.shapes()
records = rshp.records()

records contains metadata about each shape. Fields and values are not stored in a dictionary. Here is a snippet of code to do so:

{k[0]: v for k, v in zip(rshp.fields[1:], records[0])}

Here is an example of the results:

{'ORD_PRE_DI': 'SW',
'ORD_STNAME': 'SW 149TH ST',
'ORD_STREET': '149TH',
'ORD_STRE_1': 'ST',
'ORD_SUF_DI': b'  ',
'R_ADRS_FRO': 976,
...

source on GitHub