Python+Google Geocoding

　　本文主要介绍使用Python调用Google Geocoding API进行地址到地理坐标的转换。

　　Google Geocoding参考https://developers.google.com/maps/documentation/geocoding/?hl=zh-CN

　　Google Geocoding API 目前最新版为 Geocoding API (V3)

　　要通过 HTTPS 访问 Geocoding API，请使用以下形式：

　　HTTP://maps.googleapis.com/maps/geocode/out?parameters

　　这里out参数指定请求返回的数据的格式，可以是json或者xml两者之一，本文使用json进行数据获取。本例子中取官方文档中的地址进行解析：

1600 Amphitheatre Parkway, Mountain View, CA，相应的json响应为：

{
   "results" : [
      {
         "address_components" : [
            {
               "long_name" : "",
               "short_name" : "",
               "types" : [ "street_number" ]
            },
            {
               "long_name" : "Amphitheatre Parkway",
               "short_name" : "Amphitheatre Pkwy",
               "types" : [ "route" ]
            },
            {
               "long_name" : "Mountain View",
               "short_name" : "Mountain View",
               "types" : [ "locality", "political" ]
            },
            {
               "long_name" : "Santa Clara County",
               "short_name" : "Santa Clara County",
               "types" : [ "administrative_area_level_2", "political" ]
            },
            {
               "long_name" : "California",
               "short_name" : "CA",
               "types" : [ "administrative_area_level_1", "political" ]
            },
            {
               "long_name" : "United States",
               "short_name" : "US",
               "types" : [ "country", "political" ]
            },
            {
               "long_name" : "",
               "short_name" : "",
               "types" : [ "postal_code" ]
            }
         ],
         "formatted_address" : "1600 Amphitheatre Parkway, Mountain View, CA 94043, USA",
         "geometry" : {
            "location" : {
               "lat" : 37.4219998,
               "lng" : -122.0839596
            },
            "location_type" : "ROOFTOP",
            "viewport" : {
               "northeast" : {
                  "lat" : 37.4233487802915,
                  "lng" : -122.0826106197085
               },
               "southwest" : {
                  "lat" : 37.4206508197085,
                  "lng" : -122.0853085802915
               }
            }
         },
         "types" : [ "street_address" ]
      }
   ],
   "status" : "OK"
}

其中json数据中包含两个键results和status。

Demo源码：

 import urllib.request
 import json,io,os,base64
 #获得json数据
 resquest = urllib.request.urlopen('http://maps.googleapis.com/maps/api/geocode/json?address=1600+Amphitheatre+Parkway,+Mountain+View,+CA&sensor=false')
 data = resquest.read().decode('utf-8')
 jsonData = json.loads(data)
 results = jsonData['results'] #从json文件中读取results的值（形式为列表）
 address = results[0]['formatted_address']
 lat_lng = results[0]['geometry']['location']
 print(address,'的经纬度为',lat_lng)

results是一个只包含一个元素的元组，该元素(results[0])又是一个json格式的数据，包含4个键address_components、formatted_address、geometry和types。我们这里需要的地理坐标就在geometry中。