我在 C# 中有一个WCF 服务。
在服务调用客户端发送一个城市名称。我想将城市名称转换为纬度和经度，并存储在人口统计下的数据库中。
我打算使用 Google API 来实现上述功能。
我从 Google 获得了一个 API 密钥及其“服务帐户”类型。
如何使用哪些 API 获取经纬度？
我需要安装一些SDK 或任何REST 服务吗？
【问题讨论】：
标签： c# rest google-maps latitude-longitude
您可以尝试使用 NuGet 包 GoogleMaps.LocationServices，或者直接使用它的 source code。它使用 Google 的 REST API 来获取给定地址的纬度/经度，反之亦然，无需 API 密钥。
你可以这样使用它：
public static void Main()
{
var address = "Stavanger, Norway";
var locationService = new GoogleLocationService();
var point = locationService.GetLatLongFromAddress(address);
var latitude = point.Latitude;
var longitude = point.Longitude;
// Save lat/long values to DB...
}
【讨论】：
如果您想使用 Google Maps API，请查看他们的 REST API，您无需安装 Google Maps API，只需发送请求即可
http://maps.googleapis.com/maps/api/geocode/xml?address=1600+Amphitheatre+Parkway,+Mountain+View,+CA&sensor=true_or_false
你会得到一个响应 XML。
对于响应 JSON：
https://maps.googleapis.com/maps/api/geocode/json?address=1600+Estância+Sergipe,&key=**YOUR_API_KEY**
更多信息请查看
https://developers.google.com/maps/documentation/geocoding/index#GeocodingRequests
【讨论】：
您可以在特定的 url 中传递地址.. 并在返回值 dt(datatable) 中获得纬度和经度
string url = "http://maps.google.com/maps/api/geocode/xml?address=" + address+ "&sensor=false";
WebRequest request = WebRequest.Create(url);
using (WebResponse response = (HttpWebResponse)request.GetResponse())
{
using (StreamReader reader = new StreamReader(response.GetResponseStream(), Encoding.UTF8))
{
DataSet dsResult = new DataSet();
dsResult.ReadXml(reader);
DataTable dtCoordinates = new DataTable();
dtCoordinates.Columns.AddRange(new DataColumn[4] { new DataColumn("Id", typeof(int)),
new DataColumn("Address", typeof(string)),
new DataColumn("Latitude",typeof(string)),
new DataColumn("Longitude",typeof(string)) });
foreach (DataRow row in dsResult.Tables["result"].Rows)
{
string geometry_id = dsResult.Tables["geometry"].Select("result_id = " + row["result_id"].ToString())[0]["geometry_id"].ToString();
DataRow location = dsResult.Tables["location"].Select("geometry_id = " + geometry_id)[0];
dtCoordinates.Rows.Add(row["result_id"], row["formatted_address"], location["lat"], location["lng"]);
}
}
return dtCoordinates;
}
【讨论】：
/*Ready to use code : simple copy paste GetLatLong*/
public class AddressComponent
{
public string long_name { get; set; }
public string short_name { get; set; }
public List<string> types { get; set; }
}
public class Northeast
{
public double lat { get; set; }
public double lng { get; set; }
}
public class Southwest
{
public double lat { get; set; }
public double lng { get; set; }
}
public class Bounds
{
public Northeast northeast { get; set; }
public Southwest southwest { get; set; }
}
public class Location
{
public double lat { get; set; }
public double lng { get; set; }
}
public class Northeast2
{
public double lat { get; set; }
public double lng { get; set; }
}
public class Southwest2
{
public double lat { get; set; }
public double lng { get; set; }
}
public class Viewport
{
public Northeast2 northeast { get; set; }
public Southwest2 southwest { get; set; }
}
public class Geometry
{
public Bounds bounds { get; set; }
public Location location { get; set; }
public string location_type { get; set; }
public Viewport viewport { get; set; }
}
public class Result
{
public List<AddressComponent> address_components { get; set; }
public string formatted_address { get; set; }
public Geometry geometry { get; set; }
public string place_id { get; set; }
public List<string> types { get; set; }
}
public class RootObject
{
public List<Result> results { get; set; }
public string status { get; set; }
}
public static RootObject GetLatLongByAddress(string address)
{
var root = new RootObject();
var url =
string.Format(
"http://maps.googleapis.com/maps/api/geocode/json?address={0}&sensor=true_or_false", address);
var req = (HttpWebRequest)WebRequest.Create(url);
var res = (HttpWebResponse)req.GetResponse();
using (var streamreader=new StreamReader(res.GetResponseStream()))
{
var result = streamreader.ReadToEnd();
if (!string.IsNullOrWhiteSpace(result))
{
root = JsonConvert.DeserializeObject<RootObject>(result);
}
}
return root;
}
/* Call This*/
var destination_latLong = GetLatLongByAddress(um.RouteDestination);
var lattitude =Convert.ToString( destination_latLong.results[0].geometry.location.lat, CultureInfo.InvariantCulture);
var longitude=Convert.ToString( destination_latLong.results[0].geometry.location.lng, CultureInfo.InvariantCulture);
【讨论】：
Google 的替代品是OpenStreetMap's Nominatim APIs。
与 Google 不同，只要您不过度使用它们（每秒超过 1 个请求），它们就没有每日限制。下面的代码适用于 Blazor 服务器。
[Inject] IJSRuntime _js { get; set; }
public async Task<Coordinates> GetCoordinates(string city) {
Coordinates coordinates = new Coordinates();
string query= String.Format("https://nominatim.openstreetmap.org/search.php?q={0}&format=jsonv2", city);
string result = GetRequest(query); //returns a stringified array of js objects
IJSObjectReference objArray= await _js.InvokeAsync<IJSObjectReference>("JSON.parse", result); //parse the string to a js array
IJSObjectReference obj = await objArray.InvokeAsync<IJSObjectReference>("shift"); //take the first element in the array
string jsonResult = await _js.InvokeAsync<string>("JSON.stringify", obj);
dynamic dynamicResult = JObject.Parse(jsonResult);
coordinates.Latitude= dynamicResult.lat;
coordinates.Longitude= dynamicResult.lon;
return coordinates;
}
public string GetRequest(string url) {
HttpWebRequest request = (HttpWebRequest)WebRequest.Create(url);
request.AutomaticDecompression = DecompressionMethods.GZip | DecompressionMethods.Deflate;
request.UserAgent = @"Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/51.0.2704.106 Safari/537.36";
using (HttpWebResponse response = (HttpWebResponse)request.GetResponse())
using (Stream stream = response.GetResponseStream())
using (StreamReader reader = new StreamReader(stream))
{
return reader.ReadToEnd();
}
}
public class Coordinates {
public double Longitude { get; set; }
public double Latitude { get; set; }
}
【讨论】：