1.通过经纬度判断两个点之间的距离,这里面的地球半径取得是平均半径,赤道半径和极地半径是不同的,所以取平均。
public class Distance {
public static final double DEGREES_TO_RADIANS = Math.PI / 180.0;
public static final double RADIANS_TO_DEGREES = 180.0 / Math.PI;
//地球半径
public static final double EARTH_MEAN_RADIUS_KM = 6371.009;
//地球直径
private static final double EARTH_MEAN_DIAMETER = EARTH_MEAN_RADIUS_KM * 2;
/***
* 距离半径计算方式
* @param latCenterRad 中心点经纬度
* @param lonCenterRad
* @param latVals 目标经纬度
* @param lonVals
* @return 两坐标的距离 单位千米
*
*/
public static double doubleVal(double latCenterRad, double lonCenterRad, double latVals, double lonVals) {
//计算经纬度
double latRad = latVals * DEGREES_TO_RADIANS;
double lonRad = lonVals * DEGREES_TO_RADIANS;
//计算经纬度的差
double diffX = latCenterRad * DEGREES_TO_RADIANS - latRad;
double diffY = lonCenterRad * DEGREES_TO_RADIANS - lonRad;
//计算正弦和余弦
double hsinX = Math.sin(diffX * 0.5);
double hsinY = Math.sin(diffY * 0.5);
double latCenterRad_cos = Math.cos(latCenterRad * DEGREES_TO_RADIANS);
double h = hsinX * hsinX
+ (latCenterRad_cos * Math.cos(latRad) * hsinY * hsinY);
return (EARTH_MEAN_DIAMETER * Math.atan2(Math.sqrt(h), Math.sqrt(1 - h)));
}
public static void main(String[] args) {
double v = doubleVal(116.34455, 39.954588, 116.31791, 39.9354);
System.out.println(v);
}
}
2.根据提供的经度和纬度、以及半径,取得此半径内的最大最小经纬度
public class LngLat_Test {
private static double PI = 3.14159265;
private static double EARTH_RADIUS = 6378137;
private static double RAD = Math.PI / 180.0;
/// <summary>
/// 根据提供的经度和纬度、以及半径,取得此半径内的最大最小经纬度
/// </summary>
/// <param name="lat">纬度</param>
/// <param name="lon">经度</param>
/// <param name="raidus">半径(米)</param>
/// <returns></returns>
public static double[] GetAround( double lon,double lat, int raidus)
{
Double latitude = lat;
Double longitude = lon;
Double degree = (24901 * 1609) / 360.0;
double raidusMile = raidus;
Double dpmLat = 1 / degree;
Double radiusLat = dpmLat * raidusMile;
Double minLat = latitude - radiusLat;
Double maxLat = latitude + radiusLat;
Double mpdLng = degree * Math.cos(latitude * (PI / 180));
Double dpmLng = 1 / mpdLng;
Double radiusLng = dpmLng * raidusMile;
Double minLng = longitude - radiusLng;
Double maxLng = longitude + radiusLng;
return new double[] { minLat, minLng, maxLat, maxLng };
}
//116.292372,39.956232
//116.460491,39.966788
public static void main(String[] args) {
double lat=39.913833;//纬度
double lon=116.280423; //经度
int raidus=1000;//半径(米)
double[] ds = GetAround(lon,lat, raidus);
for (double d : ds) {
System.out.println(d);
}
}
}
3.将火星/高德坐标转变成百度坐标
public class GD_2_Baidu {
/**
*
*/
private static double x_pi = 3.14159265358979324 * 3000.0 / 180.0;
public void bd_encrypt(double lng, double lat) {
try {
double x = lng, y = lat;
double z = Math.sqrt(x * x + y * y) + 0.00002 * Math.sin(y * x_pi);
double theta = Math.atan2(y, x) + 0.000003 * Math.cos(x * x_pi);
double tempLon = z * Math.cos(theta) + 0.0065;
double tempLat = z * Math.sin(theta) + 0.006;
} catch (Exception e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
}
4.经纬度 的geohash值的取值,当然不同的设置可以有不同的精度
package geoHash; /**
*@Description: GeoHash实现经纬度的转化
*/
import java.util.ArrayList;
import java.util.Arrays;
import java.util.List;
public class GeoHash {
private LocationBean location;
/**
* 1 2500km;2 630km;3 78km;4 30km
* 5 2.4km; 6 610m; 7 76m; 8 19m
*/
private int hashLength = 8; //经纬度转化为geohash长度
private int latLength = 20; //纬度转化为二进制长度
private int lngLength = 20; //经度转化为二进制长度
private double minLat;//每格纬度的单位大小
private double minLng;//每个经度的倒下
private static final char[] CHARS = {'0', '1', '2', '3', '4', '5', '6', '7',
'8', '9', 'b', 'c', 'd', 'e', 'f', 'g', 'h', 'j', 'k', 'm', 'n',
'p', 'q', 'r', 's', 't', 'u', 'v', 'w', 'x', 'y', 'z'};
public GeoHash(double lat, double lng) {
location = new LocationBean(lat, lng);
setMinLatLng();
}
/**
* @Author:lulei
* @Description: 设置经纬度的最小单位
*/
private void setMinLatLng() {
minLat = LocationBean.MAXLAT - LocationBean.MINLAT;
for (int i = 0; i < latLength; i++) {
minLat /= 2.0;
}
minLng = LocationBean.MAXLNG - LocationBean.MINLNG;
for (int i = 0; i < lngLength; i++) {
minLng /= 2.0;
}
}
/**
* @return
* @Author:lulei
* @Description: 求所在坐标点及周围点组成的九个
*/
public List<String> getGeoHashBase32For9() {
double leftLat = location.getLat() - minLat;
double rightLat = location.getLat() + minLat;
double upLng = location.getLng() - minLng;
double downLng = location.getLng() + minLng;
List<String> base32For9 = new ArrayList<String>();
//左侧从上到下 3个
String leftUp = getGeoHashBase32(leftLat, upLng);
if (!(leftUp == null || "".equals(leftUp))) {
base32For9.add(leftUp);
}
String leftMid = getGeoHashBase32(leftLat, location.getLng());
if (!(leftMid == null || "".equals(leftMid))) {
base32For9.add(leftMid);
}
String leftDown = getGeoHashBase32(leftLat, downLng);
if (!(leftDown == null || "".equals(leftDown))) {
base32For9.add(leftDown);
}
//中间从上到下 3个
String midUp = getGeoHashBase32(location.getLat(), upLng);
if (!(midUp == null || "".equals(midUp))) {
base32For9.add(midUp);
}
String midMid = getGeoHashBase32(location.getLat(), location.getLng());
if (!(midMid == null || "".equals(midMid))) {
base32For9.add(midMid);
}
String midDown = getGeoHashBase32(location.getLat(), downLng);
if (!(midDown == null || "".equals(midDown))) {
base32For9.add(midDown);
}
//右侧从上到下 3个
String rightUp = getGeoHashBase32(rightLat, upLng);
if (!(rightUp == null || "".equals(rightUp))) {
base32For9.add(rightUp);
}
String rightMid = getGeoHashBase32(rightLat, location.getLng());
if (!(rightMid == null || "".equals(rightMid))) {
base32For9.add(rightMid);
}
String rightDown = getGeoHashBase32(rightLat, downLng);
if (!(rightDown == null || "".equals(rightDown))) {
base32For9.add(rightDown);
}
return base32For9;
}
/**
* @param length
* @return
* @Author:lulei
* @Description: 设置经纬度转化为geohash长度
*/
public boolean sethashLength(int length) {
if (length < 1) {
return false;
}
hashLength = length;
latLength = (length * 5) / 2;
if (length % 2 == 0) {
lngLength = latLength;
} else {
lngLength = latLength + 1;
}
setMinLatLng();
return true;
}
/**
* @return
* @Author:lulei
* @Description: 获取经纬度的base32字符串
*/
public String getGeoHashBase32() {
return getGeoHashBase32(location.getLat(), location.getLng());
}
/**
* @param lat
* @param lng
* @return
* @Author:lulei
* @Description: 获取经纬度的base32字符串
*/
private String getGeoHashBase32(double lat, double lng) {
boolean[] bools = getGeoBinary(lat, lng);
if (bools == null) {
return null;
}
StringBuffer sb = new StringBuffer();
for (int i = 0; i < bools.length; i = i + 5) {
boolean[] base32 = new boolean[5];
for (int j = 0; j < 5; j++) {
base32[j] = bools[i + j];
}
char cha = getBase32Char(base32);
if (' ' == cha) {
return null;
}
sb.append(cha);
}
return sb.toString();
}
/**
* @param base32
* @return
* @Author:lulei
* @Description: 将五位二进制转化为base32
*/
private char getBase32Char(boolean[] base32) {
if (base32 == null || base32.length != 5) {
return ' ';
}
int num = 0;
for (boolean bool : base32) {
num <<= 1;
if (bool) {
num += 1;
}
}
return CHARS[num % CHARS.length];
}
/**
* @param lat
* @param lng
* @return
* @Author:lulei
* @Description: 获取坐标的geo二进制字符串
*/
private boolean[] getGeoBinary(double lat, double lng) {
boolean[] latArray = getHashArray(lat, LocationBean.MINLAT, LocationBean.MAXLAT, latLength);
boolean[] lngArray = getHashArray(lng, LocationBean.MINLNG, LocationBean.MAXLNG, lngLength);
return merge(latArray, lngArray);
}
/**
* @param latArray
* @param lngArray
* @return
* @Author:lulei
* @Description: 合并经纬度二进制
*/
private boolean[] merge(boolean[] latArray, boolean[] lngArray) {
if (latArray == null || lngArray == null) {
return null;
}
boolean[] result = new boolean[lngArray.length + latArray.length];
Arrays.fill(result, false);
for (int i = 0; i < lngArray.length; i++) {
result[2 * i] = lngArray[i];
}
for (int i = 0; i < latArray.length; i++) {
result[2 * i + 1] = latArray[i];
}
return result;
}
/**
* @param value
* @param min
* @param max
* @return
* @Author:lulei
* @Description: 将数字转化为geohash二进制字符串
*/
private boolean[] getHashArray(double value, double min, double max, int length) {
if (value < min || value > max) {
return null;
}
if (length < 1) {
return null;
}
boolean[] result = new boolean[length];
for (int i = 0; i < length; i++) {
double mid = (min + max) / 2.0;
if (value > mid) {
result[i] = true;
min = mid;
} else {
result[i] = false;
max = mid;
}
}
return result;
}
// public static void main(String[] args) {
// // TODO Auto-generated method stub
// GeoHash g1 = new GeoHash(39.92116161986104, 116.42291855642424);
//// GeoHash g5 = new GeoHash(40.222910, 116.248980);
// GeoHash g2 = new GeoHash(39.91217638013896, 116.41120344357577);
//// GeoHash g3 = new GeoHash(40.222002, 116.248203);
//// GeoHash g4 = new GeoHash(40.222112, 116.248383);
//
// System.out.println(g1.getGeoHashBase32());
// System.out.println(g2.getGeoHashBase32());
//// System.out.println(g3.getGeoHashBase32());
//// System.out.println(g4.getGeoHashBase32());
//// System.out.println(g5.getGeoHashBase32());
// }
public static String getGeoHash(double lng,double lat){
GeoHash g4 = new GeoHash(lat, lng);
return g4.getGeoHashBase32();
}
}