c# – 知道地址时如何获取坐标？

我从Adam Freeman的“Metro Revealed：使用XAML和C#构建 Windows 8应用程序”的书中导出/修改了以下代码,以便在坐标知道时获取地址：

public static async Task<string> GetAddressForCoordinates(double latitude,double longitude)
{
    HttpClient httpClient = new HttpClient {BaseAddress = new Uri("http://nominatim.openstreetmap.org")};
    HttpResponseMessage httpResult = await httpClient.GetAsync(
        String.Format("reverse?format=json&lat={0}&lon={1}",latitude,longitude));
JsonObject jsonObject = JsonObject.Parse(await httpResult.Content.ReadAsStringAsync());

return jsonObject.GetNamedObject("address").GetNamedString("road");

}

如何得到相反的(如果地址是已知的坐标)？

UPDATE

我为此增加赏金;我已经(如上所示)是反向地理编码(获取坐标的地址);我需要的是地理编码(获取地址的坐标).

根据我上面的反向地理编码代码,我猜这可能是这样的：

public static async Task<string> GetCoordinatesForAddress(string address)
{
    HttpClient httpClient = new HttpClient {BaseAddress = new Uri("http://nominatim.openstreetmap.org")};
    HttpResponseMessage httpResult = await httpClient.GetAsync(
        String.Format("format=json&address={0}",address));

    JsonObject jsonObject = JsonObject.Parse(await httpResult.Content.ReadAsStringAsync());

    return jsonObject.GetNamedObject("address").GetNamedString("lat"); // <-- what about "lon"?
}

…但是我不知道如何组合两个坐标(经度和纬度)值(假设这是正确的或接近正确的).任何人都可以验证这一点,清理它,或提供更好的例子(使用nominatim或其他)？

更新2

回答Peter Ritchie的问题/评论如下：

在原始(反向地理编码代码)中,我有：

return jsonObject.GetNamedObject("address").GetNamedString("road");

它只是返回路;所以我假设像“157河滨大道”一样.

但是,对于地理编码(需要两个值,经度和纬度),我有这个伪代码：

return jsonObject.GetNamedObject("address").GetNamedString("lat"); // <-- what about "lon"?

所以我不知道是否需要从Task< string>中更改返回值.到任务<列出和调用(详细的伪代码)[注意：我有一个困难的时候逃脱角色括号为任务与列表的字符串]：

var latitude jsonObject.GetNamedObject("address").GetNamedString("lat");
var longitude jsonObject.GetNamedObject("address").GetNamedString("lat");
List<string> listCoordinates = new List<string>();
listCoordinates.Add(latitude);
listCoordinates.Add(longitude);
return listCoordinates;

…或者这样：

string latitude jsonObject.GetNamedObject("address").GetNamedString("lat");
string longtude jsonObject.GetNamedObject("address").GetNamedString("long");
return string.Format("{0};{1}",longitude);

…要么 ？？？

更新3

响应提供的Json代码进行地理编码：

根据原来的反向地理编码代码,不应该更像是这样：

HttpClient httpClient = new HttpClient { BaseAddress = new Uri("http://nominatim.openstreetmap.org/") };
var httpResult = await httpClient.GetAsync(
    String.Format("search?format=json&addressdetails={0}",address);

…但无论如何：
JArray类型不能被识别,
虽然JsonValue是JValue类型,但是无法识别JValue类型.
JsonConverter类型无法识别;也许是Json.Net的一部分？

最接近我可以得到编译代码的代码是：

var result = await httpResult.Content.ReadAsStringAsync();
var r = (JsonArray)JsonConverter.DeserializeObject(result);//<-- JsonConvert[er] not recognized; part of Json.NET?
var latString = ((JsonValue)r[0]["lat"]).ValueType as string;
var longString = ((JsonValue)r[0]["lon"]).ValueType as string;

…但是即使这样(接近但没有Bob Seger),JsonConvert以及JsonConverter都不被识别.

更新4

通过http://wiki.openstreetmap.org/wiki/Nominatim#Search的文档更加一致地发表了口号,我认为我的原始(反向地理编码)方法可能会更好：

public static async Task`<string`> GetAddressForCoordinates(double latitude,double longitude)
{
    HttpClient httpClient = new HttpClient {BaseAddress = new Uri("http://nominatim.openstreetmap.org/")};
    HttpResponseMessage httpResult = await httpClient.GetAsync(
        String.Format("reverse?format=json&lat={0}&lon={1}",longitude));

    JsonObject jsonObject = JsonObject.Parse(await httpResult.Content.ReadAsStringAsync());

    string house = jsonObject.GetNamedObject("addressparts").GetNamedString("house");
    string road = jsonObject.GetNamedObject("addressparts").GetNamedString("road");
    string city = jsonObject.GetNamedObject("addressparts").GetNamedString("city");
    string state = jsonObject.GetNamedObject("addressparts").GetNamedString("state");
    string postcode = jsonObject.GetNamedObject("addressparts").GetNamedString("postcode");
    string country = jsonObject.GetNamedObject("addressparts").GetNamedString("country");
    return string.Format("{0} {1},{2},{3} {4} ({5})",house,road,city,state,postcode,country);
}

这将返回,对于相应的坐标参数传递,如：“157河滨大道,香槟,IL 55555(美国)”

关于文件我觉得奇怪的是地址部分中没有“状态”元素;如果这真的是真的,而不仅仅是一个文档监督,我上面的代码将在GetNamedString(“state”)的调用失败.

我仍然不能确定正确的语法等于相反的(geocode)方法,在传入地址后获得坐标.

更新5

好的,我下载了Json.NET并编译它.我还没有测试,但我已经将彼得·里奇(Peter Ritchie)标记为(50分)答案.

这是我使用的代码：

public static async Task<string> GetCoordinatesForAddress(string address)
{
    HttpClient httpClient = new HttpClient { BaseAddress = new Uri("http://nominatim.openstreetmap.org/") };
    HttpResponseMessage httpResult = await httpClient.GetAsync(
        String.Format("search?q={0}&format=json&addressdetails=1",Pluggify(address))); // In my Pluggify() method,I replace spaces with + and then lowercase it all

    var result = await httpResult.Content.ReadAsStringAsync();
    var r = (JArray)JsonConvert.DeserializeObject(result);
    var latString = ((JValue)r[0]["lat"]).Value as string;
    var longString = ((JValue)r[0]["lon"]).Value as string;
    return string.Format("{0};{1}",latString,longString);
}

也：
一个有趣的事情发生在回到这个论坛的路上：在通过NuGet安装Json.NET的同时,我也看到“.NET的最快的JSON串行器由ServiceStack”声称比Json.NET快3倍. FIWW,它最近比Json.NET更新.思考/反应？

更新6

我有这个代码实现这个(应用程序ID和代码已被更改以保护半无辜
(我))：

// If address has not been explicitly entered,try to suss it out:
                    address = textBoxAddress1.Text.Trim();
                    lat = textBoxLatitude1.Text.Trim();
                    lng = textBoxLongitude1.Text.Trim();
                    if (string.IsNullOrWhiteSpace(address))
                    {
                        address = await SOs_Classes.SOs_Utils.GetAddressForCoordinates(lat,lng);
                    }

. . .

        public async static Task<string> GetAddressForCoordinates(string latitude,string longitude)
        {
            string currentgeoLoc = string.Format("{0},{1}",longitude);
            string queryString = string.Empty;
            string nokiaAppID = "j;dsfj;fasdkdf";
            object nokiaAppCode = "-14-14-1-7-47-178-78-4";
            var hereNetUrl = string.Format(
                "http://demo.places.nlp.nokia.com/places/v1/discover/search?at={0}&q={1}&app_id={2}    
&app_code={3}&accept=application/json",currentgeoLoc,queryString,nokiaAppID,nokiaAppCode);    
            // get data from HERE.net REST API
            var httpClient = new HttpClient();
            var hereNetResponse = await httpClient.GetStringAsync(hereNetUrl);    
            // deseralize JSON from Here.net 
            using (var tr = new StringReader(hereNetResponse))
            using (var jr = new JsonTextReader(tr))
            {
                var rootObjectResponse = new JsonSerializer    
().Deserialize<JsonDOTNetHelperClasses.RootObject>(jr);    
                var firstplace = rootObjectResponse.results.items.First();
                return HtmlUtilities.ConvertToText(firstplace.vicinity);
                // NOTE: There is also a title (such as "Donut Shop","Fire stations",etc.?) and type (such as "residence" or "business",etc.?)
            }
        }

…但在GetAddressForCoordinates()中的这一行：

var firstplace = rootObjectResponse.results.items.First();

…我得到这个错误msg：“* System.InvalidOperationException未被用户代码处理
的HResult = -2146233079
Message = Sequence不包含元素
来源= System.Core程序
堆栈跟踪：
在System.Linq.Enumerable.First [TSource](IEnumerable`1源)
在SpaceOverlays.SOs_Classes.SOs_Utils.d__12.MoveNext()在c：… *“

hereNetResponse的值是：

{"results":{"items":[]},"search":{"context":{"location":{"position":[38.804967,-90.113183],"address":
{"postalCode":"62048","city":"Hartford","stateCode":"IL","county":"Madison","countryCode":"USA","country":"
USA","text":"Hartford IL 62048
USA"}},"type":"urn:nlp-types:place","href":"http://demo.places.nlp.nokia.com/places/v1/places/loc-
dmVyc2lvbj0xO3RpdGxlPUhhcnRmb3JkO2xhdD0zOC44MDQ5Njc7bG9uPS05MC4xMTMxODM7Y2l0eT1IY
XJ0Zm9yZDtwb3N0YWxDb2RlPTYyMDQ4O2NvdW50cnk9VVNBO3N0YXRlQ29kZT1JTDtjb3VudHk9TWFka
XNvbjtjYXRlZ29yeUlkPWNpdHktdG93bi12aWxsYWdl;context=Zmxvdy1pZD02YmUzZDM4Yi0wNGVhLTUyM
jgtOWZmNy1kNWNkZGM0ODI5OThfMTM1NzQyMDI1NTg1M18wXzE2MA?
app_id=F6zpNc3TjnkiCLwl_Xmh&app_code=QoAM_5BaVDZvkE2jRvc0mw"}}}

…所以看起来里面有有效的信息,比如应该返回“哈特福德,伊利诺伊州”

无论如何,一个空白的返回值不应该抛出异常,我会想…

Double latNumber;
  Double longNumber;
  if(false == Double.TryParse(latString,out latNumber)) throw new InvalidOperationException();
  if(false == Double.TryParse(longString,out longNumber)) throw new InvalidOperationException();
  var location = new Location(latNumber,longNumber);

var httpClient = new HttpClient();
    var httpResult = await httpClient.GetAsync(
        "http://nominatim.openstreetmap.org/search?q=135+pilkington+avenue,+birmingham&format=json&polygon=1&addressdetails=1");

    var result = await httpResult.Content.ReadAsStringAsync();
    var r = (JArray) JsonConvert.DeserializeObject(result);
    var latString = ((JValue) r[0]["lat"]).Value as string;
    var longString = ((JValue)r[0]["lon"]).Value as string;