什么是分级设色图？

在 Python 中可视化地理空间数据

Mary van Valkenburg

Data Science Program Manager, Nashville Software School

分级设色图的定义

米尔顿凯恩斯 LSOA 的居民平均年龄分级设色图

各国人均 GDP（PPP）的分级设色图

密度

schools_in_districts.head(2)

district  geometry                  name               lat    lng
1         (POLYGON ((-86.77 36.38... Nashville Prep    36.16 -86.85
1         (POLYGON ((-86.77 36.38... Rocketship Prep   36.17 -86.79

获取计数

school_counts = schools_in_districts.groupby(['district']).size()
print(school_counts)

district
1    30
2    11
3    19
4    18
5    36
6    21
7    13
8    10
9    12
dtype: int64

添加计数

school_counts_df = school_counts.to_frame()
school_counts_df = school_counts_df.reset_index()
school_counts_df.columns = ['district', 'school_count']

districts_with_counts = pd.merge(school_districts, school_counts_df, 
                                 on = 'district')
districts_with_counts.head(2)

district geometry           school_count
1        (POLYGON ((-86.77 36.38...  30
3        (POLYGON ((-86.75 36.40...  19

用面积归一化计数

districts_with_counts['area'] = districts_with_counts.area

districts_with_counts['school_density'] = districts_with_counts.apply(
    lambda row: row.school_count/row.area, axis = 1)

districts_with_counts.head(2)

district geometry           school_count   area    school_density
1        (POLYGON ((-86.77 36.38...    30    0.036641    818.745403
3        (POLYGON ((-86.75 36.40...    19    0.014205    1337.594495

Passons à la pratique !

在 Python 中可视化地理空间数据