通过百度地图API将百度坐标转换成GPS经纬度

2022-06-13 01:42:20

百度地图API链接：http://developer.baidu.com/map/index.php?title=webapi/guide/changeposition

百度地图API中，有GPS坐标转百度坐标的功能 
http://dev.baidu.com/wiki/static/map/API/examples/?v=1.2&0_6#0&6

http接口是：http://api.map.baidu.com/ag/coord/convert?from=0&to=4&x=116.397428&y=39.90923&callback=BMap.Convertor.cbk_7594 
返回结果坐标是通过base64加密的。 
这个转换算法百度是不会公开的，而且百度也没有提供百度坐标转成GPS坐标功能，这里我用了取巧的办法。

百度坐标和GPS坐标转换在很近的距离时偏差非常接近。 
假设你有百度坐标：x1=116.397428，y1=39.90923 
把这个坐标当成GPS坐标，通过接口获得他的百度坐标：x2=116.41004950566，y2=39.916979519873

通过计算就可以得到GPS的坐标： 
x = 2*x1-x2，y = 2*y1-y2 
x=116.38480649434001 
y=39.901480480127

在http://dev.baidu.com/wiki/static/map/API/examples/?v=1.2&0_6#0&6 将此坐标输入GPS数据项中得到的结果是：116.39743826208,39.909194650838

实现的java代码如下：

package com.dataprocess;

import java.io.BufferedReader;

import java.io.IOException;

import java.io.InputStreamReader;

import java.io.PrintWriter;

import java.net.URL;

import java.net.URLConnection;

import java.util.List;

import java.util.Map;

import java.util.regex.Matcher;

import java.util.regex.Pattern;

public class CopyOfTest {

    public static void main(String args[]){

        String params =

                "coords=114.21892734521,29.575429778924&from=1&to=5&ak=ZQU8ZGeBf95nN8wY1cNL13NP&output=json";

        String s=CopyOfTest.sendGet("http://api.map.baidu.com/geoconv/v1/?", params);

        String[] s1 = s.split("\\[");

        String[] s2 = s1[1].split(",");

        String regEx ="[^0-9.\\+\\-\\s]";

        Pattern p = Pattern.compile(regEx);

        Matcher m1 = p.matcher(s2[0]);

        Matcher m2 = p.matcher(s2[1]);

        String[] arrs1=m1.replaceAll("").trim().split("\\s");

        String[] arrs2=m2.replaceAll("").trim().split("\\s");

        System.out.println(s1[1]);

        System.out.println(arrs1[0]+" "+arrs2[0]);

    }

    public static String sendGet(String url, String param) {

        String result = "";

        BufferedReader in = null;

        try {

            String urlNameString = url  + param;

            URL realUrl = new URL(urlNameString);

            // 打开和URL之间的连接

            URLConnection connection = realUrl.openConnection();

            // 设置通用的请求属性

            connection.setRequestProperty("accept", "*/*");

            connection.setRequestProperty("connection", "Keep-Alive");

            connection.setRequestProperty("user-agent",

                    "Mozilla/4.0 (compatible; MSIE 6.0; Windows NT 5.1;SV1)");

            // 建立实际的连接

            connection.connect();

            // 获取所有响应头字段

            Map<String, List<String>> map = connection.getHeaderFields();

            // 遍历所有的响应头字段

//            for (String key : map.keySet()) {

//                System.out.println(key + "--->" + map.get(key));

//            }

            // 定义 BufferedReader输入流来读取URL的响应

            in = new BufferedReader(new InputStreamReader(

                    connection.getInputStream(),"utf-8"));

            String line;

            while ((line = in.readLine()) != null) {

                result += line;

            }

        } catch (Exception e) {

            System.out.println("发送GET请求出现异常！" + e);

            e.printStackTrace();

        }

        // 使用finally块来关闭输入流

        finally {

            try {

                if (in != null) {

                    in.close();

                }

            } catch (Exception e2) {

                e2.printStackTrace();

            }

        }

        return result;

    }

    /**

     * 向指定 URL 发送POST方法的请求

     *

     * @param url

     *            发送请求的 URL

     * @param param

     *            请求参数，请求参数应该是 name1=value1&name2=value2 的形式。

     * @return 所代表远程资源的响应结果

     */

    public static String sendPost(String url, String param) {

        PrintWriter out = null;

        BufferedReader in = null;

        String result = "";

        try {

            URL realUrl = new URL(url);

            // 打开和URL之间的连接

            URLConnection conn = realUrl.openConnection();

            // 设置通用的请求属性

            conn.setRequestProperty("accept", "*/*");

            conn.setRequestProperty("connection", "Keep-Alive");

            conn.setRequestProperty("user-agent",

                    "Mozilla/4.0 (compatible; MSIE 6.0; Windows NT 5.1;SV1)");

            // 发送POST请求必须设置如下两行

            conn.setDoOutput(true);

            conn.setDoInput(true);

            // 获取URLConnection对象对应的输出流

            out = new PrintWriter(conn.getOutputStream());

            // 发送请求参数

            out.print(param);

            // flush输出流的缓冲

            out.flush();

            // 定义BufferedReader输入流来读取URL的响应

            in = new BufferedReader(

                    new InputStreamReader(conn.getInputStream()));

            String line;

            while ((line = in.readLine()) != null) {

                result += line;

            }

        } catch (Exception e) {

            System.out.println("发送 POST 请求出现异常！"+e);

            e.printStackTrace();

        }

        //使用finally块来关闭输出流、输入流

        finally{

            try{

                if(out!=null){

                    out.close();

                }

                if(in!=null){

                    in.close();

                }

            }

            catch(IOException ex){

                ex.printStackTrace();

            }

        }

        return result;

    }    

}

同时实现读取文本中的百度经纬度坐标实现批量处理并生成gpx格式文档（可上传到openstreetmap形成轨迹）代码如下：

package com.dataprocess;

import java.io.BufferedReader;

import java.io.BufferedWriter;

import java.io.File;

import java.io.FileInputStream;

import java.io.FileNotFoundException;

import java.io.FileOutputStream;

import java.io.IOException;

import java.io.InputStreamReader;

import java.io.OutputStreamWriter;

import java.net.URL;

import java.net.URLConnection;

import java.util.List;

import java.util.Map;

import java.util.regex.Matcher;

import java.util.regex.Pattern;

public class CopyOfGenerateGpx {

    public void generate(){

        String fileNames[]={"LocationData_2015-09-15",

                "LocationData_2015-09-16"

                };

        int n = fileNames.length;

        for(String fileName: fileNames){

            //输入文件

            File filein = new File("H:\\项目数据\\测试\\"+fileName+".txt");

            //输出文件

            File fileout = new File("H:\\项目数据\\测试\\gpx\\"+fileName+".gpx");

            //输出json文件

            File jsonfile = new File("H:\\项目数据\\测试\\json\\JSON_"+fileName+".json");

            try {

                //输入流

                FileInputStream fis = new FileInputStream(filein);

                InputStreamReader isr = new InputStreamReader(fis);

                BufferedReader br = new BufferedReader(isr);

                //输出流

                FileOutputStream fos = new FileOutputStream(fileout);

                OutputStreamWriter osw = new OutputStreamWriter(fos);

                BufferedWriter bw = new BufferedWriter(osw);

                //json输出流

                FileOutputStream fos1 = new FileOutputStream(jsonfile);

                OutputStreamWriter osw1 = new OutputStreamWriter(fos1);

                BufferedWriter bw1 = new BufferedWriter(osw1);

                bw1.write("[\r\n");

                bw.write("<?xml version=\"1.0\" encoding=\"UTF-8\"?>\r\n");

                bw.write("<gpx version=\"1.1\" creator=\"OSMTrack\" xmlns:xsi=\"http://www.w3.org/2001/XMLSchema-instance\" xmlns=\"http://www.topografix.com/GPX/1/1\""

                        + " xsi:schemaLocation=\"http://www.topografix.com/GPX/1/1 http://www.topografix.com/GPX/1/1/gpx.xsd\">\r\n");

                bw.write("<trk>\r\n<trkseg>\r\n");

                String line = null;

                String regEx ="[^0-9.\\+\\-\\s]";

                Pattern p = Pattern.compile(regEx);

                while((line=br.readLine())!=null){

                    Matcher m = p.matcher(line);

                    String[] arrs=m.replaceAll("").trim().split("\\s");

                    String lonbd = arrs[2];

                    String latbd = arrs[3];

                    String params =

                            "coords="

                            + lonbd+","+latbd

                            + "&from=1&to=5&ak=ZQU8ZGeBf95nN8wY1cNL13NP&output=json";

                    String s=sendGet("http://api.map.baidu.com/geoconv/v1/?", params);

                    String[] s1 = s.split("\\[");

                    String[] s2 = s1[1].split(",");

                    Matcher m1 = p.matcher(s2[0]);

                    Matcher m2 = p.matcher(s2[1]);

                    String[] arrs1=m1.replaceAll("").trim().split("\\s");

                    String[] arrs2=m2.replaceAll("").trim().split("\\s");

                    System.out.println(s1[1]);

                    System.out.println(arrs1[0]+" "+arrs2[0]);

                    double lon = 2*Double.parseDouble(lonbd)-Double.parseDouble(arrs1[0]);

                    double lat = 2*Double.parseDouble(latbd)-Double.parseDouble(arrs2[0]);

                    String str = "<trkpt lat=\""+lat+"\" lon=\""+lon+"\"><ele>61.3</ele><time>2015-09-05T14:12:20Z</time></trkpt>";

                    bw.write(str+"\r\n");

                    String str1 = "{"

                            +"\"longitude\": "+lon

                            +",\"latitude\": "+lat

                              +"},\r\n";

                    bw1.write(str1);

                    System.out.println(str);

                }

                bw.write("</trkseg>\r\n</trk>\r\n</gpx>\r\n");

                bw.flush();

                bw1.write("]\r\n");

                bw1.flush();

                br.close();

                fis.close();

                bw.close();

                fos.close();

            } catch (FileNotFoundException e) {

                // TODO Auto-generated catch block

                e.printStackTrace();

            } catch (IOException e) {

                // TODO Auto-generated catch block

                e.printStackTrace();

            }

        }

    }

    public static String sendGet(String url, String param) {

        String result = "";

        BufferedReader in = null;

        try {

            String urlNameString = url  + param;

            URL realUrl = new URL(urlNameString);

            // 打开和URL之间的连接

            URLConnection connection = realUrl.openConnection();

            // 设置通用的请求属性

            connection.setRequestProperty("accept", "*/*");

            connection.setRequestProperty("connection", "Keep-Alive");

            connection.setRequestProperty("user-agent",

                    "Mozilla/4.0 (compatible; MSIE 6.0; Windows NT 5.1;SV1)");

            // 建立实际的连接

            connection.connect();

            // 获取所有响应头字段

            Map<String, List<String>> map = connection.getHeaderFields();

            // 遍历所有的响应头字段

//            for (String key : map.keySet()) {

//                System.out.println(key + "--->" + map.get(key));

//            }

            // 定义 BufferedReader输入流来读取URL的响应

            in = new BufferedReader(new InputStreamReader(

                    connection.getInputStream(),"utf-8"));

            String line;

            while ((line = in.readLine()) != null) {

                result += line;

            }

        } catch (Exception e) {

            System.out.println("发送GET请求出现异常！" + e);

            e.printStackTrace();

        }

        // 使用finally块来关闭输入流

        finally {

            try {

                if (in != null) {

                    in.close();

                }

            } catch (Exception e2) {

                e2.printStackTrace();

            }

        }

        return result;

    }

    public static void main(String[] args){

        CopyOfGenerateGpx g = new CopyOfGenerateGpx();

        g.generate();

    }

}
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