如何获得 choropleth Folium 的颜色变化？

Question

我肯定在分区表配置中遗漏了一些东西。请找到以下代码。

import pandas as pd
import folium
df = pd.read_csv("https://cocl.us/sanfran_crime_dataset",index_col=0)

# group by neighborhood
sf = df.groupby('PdDistrict').count()
sf = pd.DataFrame(sf,columns=['Category'])  # remove unneeded columns
sf.reset_index(inplace=True)   # default index, otherwise groupby column becomes index
sf.rename(columns={'PdDistrict':'Neighborhood','Category':'Count'}, inplace=True)
sf.sort_values(by='Count', inplace=True, ascending=False)
sf

# San Francisco latitude and longitude values
latitude = 37.77
longitude = -122.42
sf_neighborhood_geo = 'https://raw.githubusercontent.com/codeforamerica/click_that_hood/master/public/data/san-francisco.geojson'

# Create map
sf_map = folium.Map(location=[latitude,longitude], zoom_start=12)

# Use json file  TEST based on class
sf_map.choropleth(
       geo_data=sf_neighborhood_geo,
       data=sf,
       columns=['Neighborhood','Count'],
       key_on='name',
       fill_color='YlOrRd',
       fill_opacity='0.7',
       line_opacity='0.3',
       legend_name='Crime Rate in San Francisco, by Neighborhood')

folium.LayerControl().add_to(sf_map)

# display the map
sf_map

请告诉我哪个部分不正确？

Answer 1

首先，请使用已弃用的class folium.Choropleth() instead of method choropleth()。

例如，对于你的问题：

m = folium.Map(location=[latitude,longitude], zoom_start=12)

folium.Choropleth(geo_data=sf_neighborhood_geo,
                  name='choropleth',
                  data=sf,
                  columns=['Neighborhood','Count'],
                  key_on='feature.properties.name',
                  fill_color='YlOrRd',
                  fill_opacity=0.7,
                  line_opacity=0.2,
                  legend_name='Crime Rate in San Francisco, by Neighborhood').add_to(m)

folium.LayerControl().add_to(m)

话说回来，你的代码有两个问题：

根据geojson文件，key_on='name'应该是key_on='feature.properties.name'
您 DataFrame 中的列 Neighborhood 没有包含在 geojson 文件中的名称，因此您可能会获得这样的地图：

为了获得有意义的等值线图，sf_neighborhood_geo 中的名称应对应于 sf['Neighborhood'] 中的值。

如何获得 choropleth Folium 的颜色变化？

How to get variation of the color in choropleth Folium?

python

python-3.x

pandas

choropleth

folium