Python实现OSM地图数据解析——Pydriosm-优快云博客

1. Pydriosm简介

Pydriosm是一个开源的OSM地图文件下载和解析工具。通过OSM官方API为研究人员/从业者提供OSM地图文件在线下载和本地OSM地图文件读取解析功能，以及便捷的PostgreSQL数据库接口。

2. 安装

pip install pydriosm

3. 使用方法

3.1 下载数据

（1）查看支持的文件下载格式

>>>from pydriosm import GeofabrikDownloader
>>>geofabrik_downloader = GeofabrikDownloader()
>>>geofabrik_download_catalogue = geofabrik_downloader.get_download_catalogue()
>>>print(geofabrik_download_catalogue.columns.tolist())
['Subregion', 'SubregionURL', '.osm.pbf', '.osm.pbf.Size', '.shp.zip', '.osm.bz2']

（2）查看下载链接列表

>>>print(geofabrik_download_catalogue.head())
 		Subregion  ...                                           .osm.bz2
0       Algeria  ...  http://download.geofabrik.de/africa/algeria-la...
1        Angola  ...  http://download.geofabrik.de/africa/angola-lat...
2         Benin  ...  http://download.geofabrik.de/africa/benin-late...
3      Botswana  ...  http://download.geofabrik.de/africa/botswana-l...
4  Burkina Faso  ...  http://download.geofabrik.de/africa/burkina-fa...
[5 rows x 6 columns]

（3）下载地图文件

>>>subregion_name = 'London'  # case-insensitive
>>>osm_file_format = ".pbf"  # or ".osm.pbf"
>>>download_dir = "tests"

# Download the OSM PBF data of London from Geofabrik
>>>geofabrik_downloader.download_osm_data(subregion_name, osm_file_format,
                                       download_dir, verbose=True)
Confirmed to download .osm.pbf data of the following geographic region(s):
    Greater London
? [No]|Yes: yes
Downloading "greater-london-latest.osm.pbf" to "\tests" ...
Done.

（4）下载多个文件

>>>subregion_names = ['Rutland', 'West Yorkshire', 'West Midlands']

>>>paths_to_pbf = geofabrik_downloader.download_osm_data(
    subregion_names, osm_file_format, download_dir, ret_download_path=True)
    verbose=True)
Confirmed to download .osm.pbf data of the following geographic region(s):
    Rutland
    West Yorkshire
    West Midlands
? [No]|Yes: yes
Downloading "rutland-latest.osm.pbf" to "\tests" ...
Done.
Downloading "west-yorkshire-latest.osm.pbf" to "\tests" ...
Done.
Downloading "west-midlands-latest.osm.pbf" to "\tests" ...
Done.

>>>print(type(path_to_pbf))
<class 'list'>

>>>for path_to_pbf in paths_to_pbf:
>>>    print(f"'{os.path.relpath(path_to_pbf)}'")
'tests\rutland-latest.osm.pbf'
'tests\west-yorkshire-latest.osm.pbf'
'tests\west-midlands-latest.osm.pbf'

3.2 解析文件

（1）解析文件

>>>from pydriosm import GeofabrikReader
>>>geofabrik_reader = GeofabrikReader()
>>>subregion_name = 'Rutland'
>>>data_dir = download_dir  # "tests"
>>>rutland_pbf_raw = geofabrik_reader.read_osm_pbf(subregion_name, data_dir)
>>>print(type(rutland_pbf_raw))
<class 'dict'>

（2）检查point层

>>>rutland_pbf_points = rutland_pbf_raw['points']
>>>print(rutland_points.head())
											 points
0  {"type": "Feature", "geometry": {"type": "Poin...
1  {"type": "Feature", "geometry": {"type": "Poin...
2  {"type": "Feature", "geometry": {"type": "Poin...
3  {"type": "Feature", "geometry": {"type": "Poin...
4  {"type": "Feature", "geometry": {"type": "Poin...

（3）转换为json格式
rutland_pbf_points 中每一行都是GeoJSON格式的嵌套字典，因此可以转换为json格式：

>>>import json
>
>>>rutland_pbf_points_0 = rutland_pbf_points['points'][0]
>>>print(type(rutland_pbf_points_0))
<class 'str'>

>>>rutland_pbf_points_0_ = json.loads(rutland_pbf_points_0)
>>>print(type(rutland_pbf_points_0_))
<class 'dict'>

>>>print(list(rutland_pbf_points_0_.keys()))
['type', 'geometry', 'properties', 'id']

3.3 不同geometry 类型及其数据结构

对osm文件解析后可以得到文件中不同的geometry 类型（Point, Line,Multiline，MultiPolygon，Geometry Collection）：
在这里插入图片描述

4. 总结

pydriosm主要特色可总结为：

在线文件下载：可输入区域名称下载文件，但受所选择OSM官方API限制，对国内支持稍差，某些地区可能无法匹配；
本地文件解析：可对’.pbf/.osm.pbf’，’.shp.zip/.shp’解析，按point，line，multiline，multipolygon，relation等分类存储，便于后续数据进一步过滤，用户可根据个人需求进行数据提取；
PostgreSQL数据库API：习惯使用数据库的用户，可以直接将解析数据存入数据库。

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