一、各个坐标系的概况
以上参考自:haotsp.com
总结:
WGS84坐标系:即地球坐标系,国际上通用的坐标系。
GCJ02坐标系:即火星坐标系,WGS84坐标系经加密后的坐标系。
BD09坐标系:即百度坐标系,GCJ02坐标系经加密后的坐标系。
搜狗坐标系、图吧坐标系等,估计也是在GCJ02基础上加密而成的。
二、各个地图API采用的坐标系
API | 坐标系 |
百度地图API | 百度坐标 |
腾讯搜搜地图API | 火星坐标 |
搜狐搜狗地图API | 搜狗坐标* |
阿里云地图API | 火星坐标 |
图吧MapBar地图API | 图吧坐标 |
高德MapABC地图API | 火星坐标 |
灵图51ditu地图API | 火星坐标 |
注1:百度地图使用百度坐标,支持从地球坐标和火星坐标导入成百度坐标,但无法导出。并且批量坐标转换一次只能转换20个(待验证)。
注2:搜狗地图支持直接显示地球坐标,支持地球坐标、火星坐标、百度坐标导入成搜狗坐标,同样,搜狗坐标也无法导出。
个人认为:采用自家坐标体系,而不采用国内通用的火星坐标体系,实在是自寻短处。当然,百度是因为做的足够大、足够好,所以很霸道,也为以后一统天下而不让别人瓜分之而做准备吧。搜狗虽然用自家坐标体系,但能将地球坐标直接导入,此举也属唯一。而图吧地图不知道学什么加密方式,以前用地球坐标用的好好的,现在用图吧自己的坐标,难道是因为给百度做过所以也来了这么一招?或者沿用百度?不得而知。
本文的目的在于:做地图开发的时候,不希望被一家地图API迁就,所以采用火星坐标是正确的选择,希望本文能够对选择使用谁家API的开发者提供一点帮助吧。就我个人而言,我绝不会使用非火星坐标系统的地图API,虽然百度地图API很好很强大确实很吸引我。
以上参考自:http://rovertang.com/labs/map-compare/
三、各个坐标系的相互转换
1.火星坐标系 (GCJ-02) 与百度坐标系 (BD-09) 的转换算法,其中 bd_encrypt
将 GCJ-02 坐标转换成 BD-09 坐标, bd_decrypt
反之。
- void bd_encrypt(double gg_lat, double gg_lon, double &bd_lat, double &bd_lon)
- {
- double x = gg_lon, y = gg_lat;
- double z = sqrt(x * x + y * y) + 0.00002 * sin(y * x_pi);
- double theta = atan2(y, x) + 0.000003 * cos(x * x_pi);
- bd_lon = z * cos(theta) + 0.0065;
- bd_lat = z * sin(theta) + 0.006;
- }
- void bd_decrypt(double bd_lat, double bd_lon, double &gg_lat, double &gg_lon)
- {
- double x = bd_lon - 0.0065, y = bd_lat - 0.006;
- double z = sqrt(x * x + y * y) - 0.00002 * sin(y * x_pi);
- double theta = atan2(y, x) - 0.000003 * cos(x * x_pi);
- gg_lon = z * cos(theta);
- gg_lat = z * sin(theta);
- }
- void bd_encrypt(double gg_lat, double gg_lon, double &bd_lat, double &bd_lon)
- {
- double x = gg_lon, y = gg_lat;
- double z = sqrt(x * x + y * y) + 0.00002 * sin(y * x_pi);
- double theta = atan2(y, x) + 0.000003 * cos(x * x_pi);
- bd_lon = z * cos(theta) + 0.0065;
- bd_lat = z * sin(theta) + 0.006;
- }
- void bd_decrypt(double bd_lat, double bd_lon, double &gg_lat, double &gg_lon)
- {
- double x = bd_lon - 0.0065, y = bd_lat - 0.006;
- double z = sqrt(x * x + y * y) - 0.00002 * sin(y * x_pi);
- double theta = atan2(y, x) - 0.000003 * cos(x * x_pi);
- gg_lon = z * cos(theta);
- gg_lat = z * sin(theta);
- }
2.地球坐标系 (WGS-84) 到火星坐标系 (GCJ-02) 的转换算法
WGS-84 到 GCJ-02 的转换(即 GPS 加偏)算法
- using System;
- namespace Navi
- {
- class EvilTransform
- {
- const double pi = 3.14159265358979324;
- //
- // Krasovsky 1940
- //
- // a = 6378245.0, 1/f = 298.3
- // b = a * (1 - f)
- // ee = (a^2 - b^2) / a^2;
- const double a = 6378245.0;
- const double ee = 0.00669342162296594323;
- //
- // World Geodetic System ==> Mars Geodetic System
- public static void transform(double wgLat, double wgLon, out double mgLat, out double mgLon)
- {
- if (outOfChina(wgLat, wgLon))
- {
- mgLat = wgLat;
- mgLon = wgLon;
- return;
- }
- double dLat = transformLat(wgLon - 105.0, wgLat - 35.0);
- double dLon = transformLon(wgLon - 105.0, wgLat - 35.0);
- double radLat = wgLat / 180.0 * pi;
- double magic = Math.Sin(radLat);
- magic = 1 - ee * magic * magic;
- double sqrtMagic = Math.Sqrt(magic);
- dLat = (dLat * 180.0) / ((a * (1 - ee)) / (magic * sqrtMagic) * pi);
- dLon = (dLon * 180.0) / (a / sqrtMagic * Math.Cos(radLat) * pi);
- mgLat = wgLat + dLat;
- mgLon = wgLon + dLon;
- }
- static bool outOfChina(double lat, double lon)
- {
- if (lon < 72.004 || lon > 137.8347)
- return true;
- if (lat < 0.8293 || lat > 55.8271)
- return true;
- return false;
- }
- static double transformLat(double x, double y)
- {
- double ret = -100.0 + 2.0 * x + 3.0 * y + 0.2 * y * y + 0.1 * x * y + 0.2 * Math.Sqrt(Math.Abs(x));
- ret += (20.0 * Math.Sin(6.0 * x * pi) + 20.0 * Math.Sin(2.0 * x * pi)) * 2.0 / 3.0;
- ret += (20.0 * Math.Sin(y * pi) + 40.0 * Math.Sin(y / 3.0 * pi)) * 2.0 / 3.0;
- ret += (160.0 * Math.Sin(y / 12.0 * pi) + 320 * Math.Sin(y * pi / 30.0)) * 2.0 / 3.0;
- return ret;
- }
- static double transformLon(double x, double y)
- {
- double ret = 300.0 + x + 2.0 * y + 0.1 * x * x + 0.1 * x * y + 0.1 * Math.Sqrt(Math.Abs(x));
- ret += (20.0 * Math.Sin(6.0 * x * pi) + 20.0 * Math.Sin(2.0 * x * pi)) * 2.0 / 3.0;
- ret += (20.0 * Math.Sin(x * pi) + 40.0 * Math.Sin(x / 3.0 * pi)) * 2.0 / 3.0;
- ret += (150.0 * Math.Sin(x / 12.0 * pi) + 300.0 * Math.Sin(x / 30.0 * pi)) * 2.0 / 3.0;
- return ret;
- }
- }
- }
- using System;
- namespace Navi
- {
- class EvilTransform
- {
- const double pi = 3.14159265358979324;
- //
- // Krasovsky 1940
- //
- // a = 6378245.0, 1/f = 298.3
- // b = a * (1 - f)
- // ee = (a^2 - b^2) / a^2;
- const double a = 6378245.0;
- const double ee = 0.00669342162296594323;
- //
- // World Geodetic System ==> Mars Geodetic System
- public static void transform(double wgLat, double wgLon, out double mgLat, out double mgLon)
- {
- if (outOfChina(wgLat, wgLon))
- {
- mgLat = wgLat;
- mgLon = wgLon;
- return;
- }
- double dLat = transformLat(wgLon - 105.0, wgLat - 35.0);
- double dLon = transformLon(wgLon - 105.0, wgLat - 35.0);
- double radLat = wgLat / 180.0 * pi;
- double magic = Math.Sin(radLat);
- magic = 1 - ee * magic * magic;
- double sqrtMagic = Math.Sqrt(magic);
- dLat = (dLat * 180.0) / ((a * (1 - ee)) / (magic * sqrtMagic) * pi);
- dLon = (dLon * 180.0) / (a / sqrtMagic * Math.Cos(radLat) * pi);
- mgLat = wgLat + dLat;
- mgLon = wgLon + dLon;
- }
- static bool outOfChina(double lat, double lon)
- {
- if (lon < 72.004 || lon > 137.8347)
- return true;
- if (lat < 0.8293 || lat > 55.8271)
- return true;
- return false;
- }
- static double transformLat(double x, double y)
- {
- double ret = -100.0 + 2.0 * x + 3.0 * y + 0.2 * y * y + 0.1 * x * y + 0.2 * Math.Sqrt(Math.Abs(x));
- ret += (20.0 * Math.Sin(6.0 * x * pi) + 20.0 * Math.Sin(2.0 * x * pi)) * 2.0 / 3.0;
- ret += (20.0 * Math.Sin(y * pi) + 40.0 * Math.Sin(y / 3.0 * pi)) * 2.0 / 3.0;
- ret += (160.0 * Math.Sin(y / 12.0 * pi) + 320 * Math.Sin(y * pi / 30.0)) * 2.0 / 3.0;
- return ret;
- }
- static double transformLon(double x, double y)
- {
- double ret = 300.0 + x + 2.0 * y + 0.1 * x * x + 0.1 * x * y + 0.1 * Math.Sqrt(Math.Abs(x));
- ret += (20.0 * Math.Sin(6.0 * x * pi) + 20.0 * Math.Sin(2.0 * x * pi)) * 2.0 / 3.0;
- ret += (20.0 * Math.Sin(x * pi) + 40.0 * Math.Sin(x / 3.0 * pi)) * 2.0 / 3.0;
- ret += (150.0 * Math.Sin(x / 12.0 * pi) + 300.0 * Math.Sin(x / 30.0 * pi)) * 2.0 / 3.0;
- return ret;
- }
- }
- }
以上参考自:http://www.xue5.com/Mobile/iOS/679842.html
3.百度在线转换API
- http://api.map.baidu.com/ag/coord/convert?from=0&to=4&x=longitude&y=latitude
- from: 来源坐标系 (0表示原始GPS坐标,2表示Google坐标)
- to: 转换后的坐标 (4就是百度自己啦,好像这个必须是4才行)
- x: 精度
- y: 纬度
- http://api.map.baidu.com/ag/coord/convert?from=0&to=4&x=longitude&y=latitude
- from: 来源坐标系 (0表示原始GPS坐标,2表示Google坐标)
- to: 转换后的坐标 (4就是百度自己啦,好像这个必须是4才行)
- x: 精度
- y: 纬度
请求之后会返回一串Json
- {
- "error":0,
- "x":"MTIxLjUwMDIyODIxNDk2",
- "y":"MzEuMjM1ODUwMjYwMTE3"
- }
- error:是结果是否出错标志位,"0"表示OK
- x: 百度坐标系的精度(Base64加密)
- y: 百度坐标系的纬度(Base64加密)
- {
- "error":0,
- "x":"MTIxLjUwMDIyODIxNDk2",
- "y":"MzEuMjM1ODUwMjYwMTE3"
- }
- error:是结果是否出错标志位,"0"表示OK
- x: 百度坐标系的精度(Base64加密)
- y: 百度坐标系的纬度(Base64加密)
什么情况,经纬度居然还加密?那接下来也只好见招拆招了
- import java.io.BufferedReader;
- import java.io.IOException;
- import java.io.InputStream;
- import java.io.InputStreamReader;
- import java.io.OutputStreamWriter;
- import java.net.URL;
- import java.net.URLConnection;
- import com.sun.org.apache.xerces.internal.impl.dv.util.Base64;
- public class BaiduAPIConverter extends Thread {
- public static void testPost(String x, String y) throws IOException {
- try {
- URL url = new URL("http://api.map.baidu.com/ag/coord/convert?from=2&to=4&x="+ x + "&y=" + y);
- URLConnection connection = url.openConnection();
- connection.setDoOutput(true);
- OutputStreamWriter out = new OutputStreamWriter(connection.getOutputStream(), "utf-8");
- // remember to clean up
- out.flush();
- out.close();
- // 一旦发送成功,用以下方法就可以得到服务器的回应:
- String sCurrentLine, sTotalString;
- sCurrentLine = sTotalString = "";
- InputStream l_urlStream;
- l_urlStream = connection.getInputStream();
- BufferedReader l_reader = new BufferedReader(new InputStreamReader(l_urlStream));
- while ((sCurrentLine = l_reader.readLine()) != null) {
- if (!sCurrentLine.equals(""))
- sTotalString += sCurrentLine;
- }
- sTotalString = sTotalString.substring(1, sTotalString.length() - 1);
- String[] results = sTotalString.split("\,");
- if (results.length == 3) {
- if (results[0].split("\:")[1].equals("0")) {
- String mapX = results[1].split("\:")[1];
- String mapY = results[2].split("\:")[1];
- mapX = mapX.substring(1, mapX.length() - 1);
- mapY = mapY.substring(1, mapY.length() - 1);
- mapX = new String(Base64.decode(mapX));
- mapY = new String(Base64.decode(mapY));
- System.out.println(" " + mapX + " " + mapY);
- }
- }
- sleep(10000);
- } catch (InterruptedException e) {
- // TODO Auto-generated catch block
- e.printStackTrace();
- }
- }
- /**
- * @param args
- * @throws IOException
- */
- public static void main(String[] args) throws IOException {
- testPost("120.151379", "30.184678");
- System.out.println("ok");
- }
- }
- import java.io.BufferedReader;
- import java.io.IOException;
- import java.io.InputStream;
- import java.io.InputStreamReader;
- import java.io.OutputStreamWriter;
- import java.net.URL;
- import java.net.URLConnection;
- import com.sun.org.apache.xerces.internal.impl.dv.util.Base64;
- public class BaiduAPIConverter extends Thread {
- public static void testPost(String x, String y) throws IOException {
- try {
- URL url = new URL("http://api.map.baidu.com/ag/coord/convert?from=2&to=4&x="+ x + "&y=" + y);
- URLConnection connection = url.openConnection();
- connection.setDoOutput(true);
- OutputStreamWriter out = new OutputStreamWriter(connection.getOutputStream(), "utf-8");
- // remember to clean up
- out.flush();
- out.close();
- // 一旦发送成功,用以下方法就可以得到服务器的回应:
- String sCurrentLine, sTotalString;
- sCurrentLine = sTotalString = "";
- InputStream l_urlStream;
- l_urlStream = connection.getInputStream();
- BufferedReader l_reader = new BufferedReader(new InputStreamReader(l_urlStream));
- while ((sCurrentLine = l_reader.readLine()) != null) {
- if (!sCurrentLine.equals(""))
- sTotalString += sCurrentLine;
- }
- sTotalString = sTotalString.substring(1, sTotalString.length() - 1);
- String[] results = sTotalString.split("\,");
- if (results.length == 3) {
- if (results[0].split("\:")[1].equals("0")) {
- String mapX = results[1].split("\:")[1];
- String mapY = results[2].split("\:")[1];
- mapX = mapX.substring(1, mapX.length() - 1);
- mapY = mapY.substring(1, mapY.length() - 1);
- mapX = new String(Base64.decode(mapX));
- mapY = new String(Base64.decode(mapY));
- System.out.println(" " + mapX + " " + mapY);
- }
- }
- sleep(10000);
- } catch (InterruptedException e) {
- // TODO Auto-generated catch block
- e.printStackTrace();
- }
- }
- /**
- * @param args
- * @throws IOException
- */
- public static void main(String[] args) throws IOException {
- testPost("120.151379", "30.184678");
- System.out.println("ok");
- }
- }
到这里也差不多好了,主要的代码都写出来了,其他的您就自己写吧。
以上参考自:http://scalpel.me/archives/136/
四、重点啊,原来百度有内置转换方法,这下可以不局限于百度定位SDK了
在百度地图中取得WGS-84坐标,调用如下方法:
BMapManager.getLocationManager().setLocationCoordinateType(MKLocationManager.MK_COORDINATE_WGS84);
这样从百度api中取得的坐标就是WGS-84了,可是这种坐标如果显示到百度地图上就会偏移,也就是说取出一个坐标,原封不动的显示上去就偏移了,所以为了显示也是正常就需要在绘制到百度地图上之前转换成BD-09。
转换成BD-09,调用方法:
GeoPoint wgs84;
GeoPoint bd09 = CoordinateConvert.bundleDecode(CoordinateConvert.fromWgs84ToBaidu(wgs84));
这里实在不明白为何要设计成CoordinateConvert.fromWgs84ToBaidu(wgs84)返回了一个Bundle,所以还需要CoordinateConvert.bundleDecode()再转成GeoPoint。
转自:http://blog.csdn.net/findsafety/article/details/12442639