谷歌地图静态地图折线穿过湖泊、河流、山脉

Question

我的程序使用网络服务的谷歌地图方向来查找两点之间的路线。结果被解析并存储在变量中。
然后使用这个变量来组成谷歌静态地图 URL。

解析和 URL 工作正常。问题是绘制的“路线”要经过湖泊和山脉。

{
    String GPS = "-22.978823,-43.233249";
    String link = MAPS_BASE_URL + "center=brazil," + GPS + 
            "&markers=color:blue|brazil," + GPS +
            "&path=color:0xff0000ff" + "%s" + 
            "&zoom=13&size=1024x1024&sensor=false"; 
    String htmlContent = "";
    String direction_URL= "";

    URL url = null;
    String parsedStr = null;
    Scanner scan = null;

    origin = GPS;
    destination ="Maracanã";

    try { 
        direction_URL = MAPS_DIRECTIONS_URL;    
        direction_URL += URLEncoder.encode(origin, "UTF-8");
        direction_URL += "&destination=";
        direction_URL += URLEncoder.encode(destination, "UTF-8");
        direction_URL += "&key=AIzaSyARNFl6ns__p2OEy3uCrZMGem8KW8pXwAI";
    }catch(UnsupportedEncodingException e){
         Logger.getLogger(Service.class.getName()).log(Level.SEVERE, null, e);
    }

    try {
        url = new URL(direction_URL);
    } catch (MalformedURLException ex) {
        Logger.getLogger(AlertService.class.getName()).log(Level.SEVERE, null, ex);
    }

    try {
        scan = new Scanner(url.openStream());
    } catch (IOException ex) {
        Logger.getLogger(AlertService.class.getName()).log(Level.SEVERE, null, ex);
    }

    String str = new String();
    while (scan.hasNext())
        str += scan.nextLine();
    scan.close();

    parsedStr = parseJson(str);

    try {
        InputStream htmlInputStream = 
                AlertService.class.getResourceAsStream("/resources/gapi.html");

        BufferedReader htmlReader = new BufferedReader(
                new InputStreamReader(htmlInputStream));

        String locationsContent = "";
        String wilcardContent = "";

        Scanner strScanner = new Scanner(parsedStr);

        while (strScanner.hasNextLine()) 
        {
            locationsContent = strScanner.nextLine() + "\n";

            StringTokenizer st = new StringTokenizer(locationsContent, ";");
            if (st.countTokens() == 2)
                wilcardContent += "|" + st.nextToken().trim()
                        + "," + st.nextToken().trim();
        }
        link = link.replaceFirst("%s", wilcardContent);

        htmlContent = "";
        while (htmlReader.ready()) 
            htmlContent += htmlReader.readLine() + "\n";

        htmlContent = htmlContent.replaceAll("%s", link);

     } catch (FileNotFoundException ex) {
        Logger.getLogger(Service.class.getName()).log(Level.SEVERE, null, ex);
    } catch (IOException ex) {
        Logger.getLogger(Service.class.getName()).log(Level.SEVERE, null, ex);
    } 
   return htmlContent;
}

解析函数：

 private String parseJson(String s){
    String  coordinates = new String ();
    final JSONObject json = new JSONObject(s);
    final JSONObject jsonRoute = json.getJSONArray("routes").getJSONObject(0);
    //Get the leg, only one leg as we don't support waypoints
    final JSONObject leg = jsonRoute.getJSONArray("legs").getJSONObject(0);
    //Get the steps for this leg
    final JSONArray steps = leg.getJSONArray("steps");
    //Number of steps for use in for loop
    final int numSteps = steps.length();

    for(int i = 0; i< numSteps; ++i){
        final JSONObject step = steps.getJSONObject(i);

        final JSONObject startLocation = step.getJSONObject("start_location");
        final Double startLat = startLocation.getDouble("lat");
        final Double startlng = startLocation.getDouble("lng");

        final JSONObject endLocation = step.getJSONObject("end_location");
        final Double endtLat = endLocation.getDouble("lat");
        final Double endtlng = endLocation.getDouble("lng");

        coordinates = coordinates.concat(" ");    
        coordinates = coordinates.concat(startLat.toString());
        coordinates = coordinates.concat(";" + " ");
        coordinates = coordinates.concat(startlng.toString());
        coordinates = coordinates.concat("\n");  

        coordinates = coordinates.concat(" ");    
        coordinates = coordinates.concat(endtLat.toString());
        coordinates = coordinates.concat(";" + " ");
        coordinates = coordinates.concat(endtlng.toString());
        coordinates = coordinates.concat("\n");      
    } 
    return coordinates;     
}

Json 响应：

https://maps.googleapis.com/maps/api/directions/json?origin=-22.978823,-43.233249&destination=Maracan%C3%A2&key=AIzaSyARNFl6ns__p2OEy3uCrZMGem8KW8pXwAI

最终到达网址如下所示：

http://maps.google.com/maps/api/staticmap?center=brazil,-22.978823,-43.233249&markers=color:blue|brazil,-22.978823,-43.233249&path=color:0xff0000ff|-22.9783362,-43.2336781|-22.9772355,-43.23076390000001|-22.9772355,-43.23076390000001|-22.9789792,-43.2300162|-22.9789792,-43.2300162|-22.9790772,-43.23036|-22.9790772,-43.23036|-22.9786979,-43.22698949999999|-22.9786979,-43.22698949999999|-22.9771399,-43.2196208|-22.9771399,-43.2196208|-22.9624962,-43.20396840000001|-22.9624962,-43.20396840000001|-22.9583858,-43.2043807|-22.9583858,-43.2043807|-22.934896,-43.2094454|-22.934896,-43.2094454|-22.9333061,-43.2096873|-22.9333061,-43.2096873|-22.913577,-43.2099889|-22.913577,-43.2099889|-22.9106681,-43.2154625|-22.9106681,-43.2154625|-22.9101261,-43.2217923|-22.9101261,-43.2217923|-22.9114561,-43.2254838|-22.9114561,-43.2254838|-22.9135546,-43.2276606&zoom=13&size=1024x1024&sensor=false

Answer 1

您需要在每个步骤的起点和终点之间包含折线路径（它是编码的折线）。

来自directions web service response：

 "steps" : [
    {
       "distance" : {
          "text" : "0.3 km",
          "value" : 335
       },
       "duration" : {
          "text" : "1 min",
          "value" : 52
       },
       "end_location" : {
          "lat" : -22.9772355,
          "lng" : -43.23076390000001
       },
       "html_instructions" : "Head \u003cb\u003enortheast\u003c/b\u003e on \u003cb\u003eR. Marquês de São Vicente\u003c/b\u003e",
       "polyline" : {
          "points" : "r}fkCna{fGyBaDMSMSOUMUCMAOOgAEe@Co@?o@?YAWEk@?G"
       },
       "start_location" : {
          "lat" : -22.9783362,
          "lng" : -43.2336781
       },
       "travel_mode" : "DRIVING"
     },
     // ...

Including all the step polylines (and encoding the polyline) works for me

jsfiddle creating a URL for the static map from the web service response

Answer 2

我想出了如何在 java 中解决它。我改编了用户 geocozip javascript 代码。就我而言，由于没有提供航点，我只需要一条腿。所以我的解析函数得到了这个：

  List<LatLng> path = new ArrayList();
  for(int j = 0; j< numSteps; ++j){
    final JSONObject step = steps.getJSONObject(j);

    final JSONObject polyline = step.getJSONObject("polyline");
    final String polylinePoint = polyline.getString("points");


    List<LatLng> coordinates = decodePath(polylinePoint);
    for( int k = 0; k < coordinates.size(); ++k){
        path.add(coordinates.get(k));
    }
 } 

还需要重新编码，然后放入可读格式的URL。

String newPath = path.createPolyLine(encodedPath);
String locationsContent="";
locationsContent = URLEncoder.encode(newPath, "UTF-8")
        .replaceAll("\\%40", "@")
        .replaceAll("\\+", "%20")
        .replaceAll("\\%21", "!")
        .replaceAll("\\%27", "'")
        .replaceAll("\\%28", "(")
        .replaceAll("\\%29", ")");