Python通过调用folium做出漂亮的地图

推荐一个超好用的python包folium, 专门用于地理数据可视化，官方英文教程教程点击这里，查看本文源代码请点击这里。

folium：https://pypi.org/project/folium/

英文教程：https://python-visualization.github.io/folium/quickstart.html

源代码：https://python-visualization.github.io/folium/quickstart.html

使用方法很简单，操作如下：

1.导入包，创建一副世界地图

import folium
import pandas as pd

In [2]:

# define the world map
world_map = folium.Map()

# display world map
world_map
2. 输入经纬度，尺度，在这里我们以旧金山（37.7749° N, 122.4194° W）为例。
# San Francisco latitude and longitude values
latitude = 37.77
longitude = -122.42

# Create map and display it
san_map = folium.Map(location=[latitude, longitude], zoom_start=12)

# Display the map of San Francisco
san_map

更改地图显示，默认为'OpenStreetMap'风格，我们还可以选择'Stamen Terrain', 'Stamen Toner'等。
# Create map and display it
san_map = folium.Map(location=[latitude, longitude], zoom_start=12,tiles='Stamen Toner')
3. 读取数据集（旧金山犯罪数据集）
# Read Dataset 
cdata = pd.read_csv('https://cocl.us/sanfran_crime_dataset')

cdata.head()
4. 在地图上显示前200条犯罪数据
# get the first 200 crimes in the cdata
limit = 200
data = cdata.iloc[0:limit, :]

# Instantiate a feature group for the incidents in the dataframe
incidents = folium.map.FeatureGroup()

# Loop through the 200 crimes and add each to the incidents feature group
for lat, lng, in zip(cdata.Y, data.X):
    incidents.add_child(
        folium.CircleMarker(
            [lat, lng],
            radius=7, # define how big you want the circle markers to be
            color='yellow',
            fill=True,
            fill_color='red',
            fill_opacity=0.4
        )
    )

# Add incidents to map
san_map = folium.Map(location=[latitude, longitude], zoom_start=12)
san_map.add_child(incidents)
5. 添加地理标签
# add pop-up text to each marker on the map
latitudes = list(data.Y)
longitudes = list(data.X)
labels = list(data.Category)

for lat, lng, label in zip(latitudes, longitudes, labels):
    folium.Marker([lat, lng], popup=label).add_to(san_map)    
    
# add incidents to map
san_map.add_child(incidents)

6. 统计区域犯罪总数
from folium import plugins

# let's start again with a clean copy of the map of San Francisco
san_map = folium.Map(location = [latitude, longitude], zoom_start = 12)

# instantiate a mark cluster object for the incidents in the dataframe
incidents = plugins.MarkerCluster().add_to(san_map)

# loop through the dataframe and add each data point to the mark cluster
for lat, lng, label, in zip(data.Y, data.X, cdata.Category):
    folium.Marker(
        location=[lat, lng],
        icon=None,
        popup=label,
    ).add_to(incidents)

# add incidents to map

san_map.add_child(incidents)
7. 读取geojson文件，可视化旧金山市10个不同Neighborhood的边界
import json
import requests

url = 'https://cocl.us/sanfran_geojson'
san_geo = f'{url}'
san_map = folium.Map(location=[37.77, -122.4], zoom_start=12)
folium.GeoJson(
    san_geo,
    style_function=lambda feature: {
        'fillColor': '#ffff00',
        'color': 'black',
        'weight': 2,
        'dashArray': '5, 5'
    }
).add_to(san_map)

#display map
san_map
8. 统计每个区域的犯罪事件数目
# Count crime numbers in each neighborhood
disdata = pd.DataFrame(cdata['PdDistrict'].value_counts())
disdata.reset_index(inplace=True)
disdata.rename(columns={'index':'Neighborhood','PdDistrict':'Count'},inplace=True)

disdata

9. 创建Choropleth Map （颜色深浅代表各区犯罪事件数目）
m = folium.Map(location=[37.77, -122.4], zoom_start=12)
folium.Choropleth(
    geo_data=san_geo,
    data=disdata,
    columns=['Neighborhood','Count'],
    key_on='feature.properties.DISTRICT',
    #fill_color='red',
    fill_color='YlOrRd',
    fill_opacity=0.7,
    line_opacity=0.2,
    highlight=True,
    legend_name='Crime Counts in San Francisco'
).add_to(m)

m

10. 创建热力图
from folium.plugins import HeatMap

# let's start again with a clean copy of the map of San Francisco
san_map = folium.Map(location = [latitude, longitude], zoom_start = 12)

# Convert data format
heatdata = data[['Y','X']].values.tolist()

# add incidents to map
HeatMap(heatdata).add_to(san_map)

san_map
本文源代码Jupyter notebook地址：https://nbviewer.jupyter.org/github/gaonanlee/Visualization-Practice/blob/master/Folium%20Visualization%20Examples.ipynb
GitHub下载地址：https://github.com/gaonanlee/Visualization-Practice/blob/master/Folium%20Visualization%20Examples.ipynb
最后，folium还可以用来创建动态热力图，动态路径图等，具体可参考Medium上的这篇文章。
https://towardsdatascience.com/data-101s-spatial-visualizations-and-analysis-in-python-with-folium-39730da2adf