Getting started¶
Feature Collections¶
The main argument required by many Geoplot functions feature_collection
is a Python dictionary containing the contents of a GeoJSON FeatureCollection. You can customise which property to use as the index. The default is 'id'
.
GeoJSON FeatureCollections for various UK geographies are available infaculty_extras.opendata
. To list available GeoJSONs:
[1]:
from faculty_extras import opendata
opendata.ls('uk_statistical_boundaries/geojson')
[1]:
['/input/geojson/',
'/input/geojson/local_authorities.json',
'/input/geojson/lower_super_output_areas.json',
'/input/geojson/middle_super_output_areas.json',
'/input/geojson/output_areas.json',
'/input/geojson/parliamentary_constituencies.json']
and to load, for example, the boundaries of th UK parliamentary constituencies:
[2]:
pcon_geojson = opendata.load('uk_statistical_boundaries/geojson/parliamentary_constituencies.json')
Create a map¶
Now let’s use geoplotz
to make a folium map centred on the feature collection:
[3]:
from faculty_extras import geoplot
folium_map = geoplot.centred_map(pcon_geojson)
We can generate a data point for each feature in the dataset:
Generate sample data¶
[4]:
import numpy as np
def lat(feature):
coords = feature['geometry']['coordinates']
while not isinstance(coords[0], (int, float)):
coords = coords[0]
return coords[1]
areas = np.array([feat['properties']['id'] for feat in pcon_geojson['features']])
data = np.array([lat(feat) for feat in pcon_geojson['features']])
Plot a single-colour map¶
[5]:
geoplot.single_colour(folium_map, pcon_geojson, 'red')
folium_map
[5]:
Plot only selected features¶
[6]:
folium_map = geoplot.centred_map(pcon_geojson)
geoplot.single_colour(folium_map, pcon_geojson, 'red', feature_selection=areas[data < 54])
folium_map
[6]:
Plot choropleth maps¶
[7]:
folium_map = geoplot.centred_map(pcon_geojson)
geoplot.choropleth(folium_map, pcon_geojson, areas, data, bins=10)
folium_map
[7]:
Alternative colours¶
[8]:
folium_map = geoplot.centred_map(pcon_geojson, zoom_start=5)
geoplot.choropleth(folium_map, pcon_geojson, areas, data, bins=10, colourmap='rainbow')
folium_map
[8]:
Save¶
[9]:
folium_map.save('map.html')