本文實例介紹了JAVA實現將GeoHash轉化為對應的經緯度坐標的詳細代碼，分享給大家供大家參考，具體內容如下
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package com.lulei.geo; import java.util.ArrayList; import java.util.Arrays; import java.util.HashMap; import java.util.List; import com.lulei.geo.bean.LocationBean; import com.lulei.util.JsonUtil; 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; //經緯度轉化為geohash長度 private int latLength = 20; //緯度轉化為二進制長度 private int lngLength = 20; //經度轉化為二進制長度 private double minLat;//每格緯度的單位大小 private double minLng;//每個經度的單位大小 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'}; private static HashMap<Character, Integer> CHARSMAP; static { CHARSMAP = new HashMap<Character, Integer>(); for (int i = 0; i < CHARS.length; i++) { CHARSMAP.put(CHARS[i], i); } } public GeoHash(double lat, double lng) { location = new LocationBean(lat, lng); setMinLatLng(); } public int gethashLength() { return hashLength; } /** * @Author:lulei * @Description: 設置經緯度的最小單位 */ 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: 求所在坐標點及周圍點組成的九個 */ 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>(); //左側從上到下 3個 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); } //中間從上到下 3個 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); } //右側從上到下 3個 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: 設置經緯度轉化為geohash長度 */ 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: 獲取經緯度的base32字符串 */ public String getGeoHashBase32() { return getGeoHashBase32(location.getLat(), location.getLng()); } /** * @param lat * @param lng * @return * @Author:lulei * @Description: 獲取經緯度的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: 將五位二進制轉化為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 i * @return * @Author:lulei * @Description: 將數字轉化為二進制字符串 */ private String getBase32BinaryString(int i) { if (i < 0 || i > 31) { return null; } String str = Integer.toBinaryString(i + 32); return str.substring(1); } /** * @param geoHash * @return * @Author:lulei * @Description: 將geoHash轉化為二進制字符串 */ private String getGeoHashBinaryString(String geoHash) { if (geoHash == null || "".equals(geoHash)) { return null; } StringBuffer sb = new StringBuffer(); for (int i = 0; i < geoHash.length(); i++) { char c = geoHash.charAt(i); if (CHARSMAP.containsKey(c)) { String cStr = getBase32BinaryString(CHARSMAP.get(c)); if (cStr != null) { sb.append(cStr); } } } return sb.toString(); } /** * @param geoHash * @return * @Author:lulei * @Description: 返回geoHash 對應的坐標 */ public LocationBean getLocation(String geoHash) { String geoHashBinaryStr = getGeoHashBinaryString(geoHash); if (geoHashBinaryStr == null) { return null; } StringBuffer lat = new StringBuffer(); StringBuffer lng = new StringBuffer(); for (int i = 0; i < geoHashBinaryStr.length(); i++) { if (i % 2 != 0) { lat.append(geoHashBinaryStr.charAt(i)); } else { lng.append(geoHashBinaryStr.charAt(i)); } } double latValue = getGeoHashMid(lat.toString(), LocationBean.MINLAT, LocationBean.MAXLAT); double lngValue = getGeoHashMid(lng.toString(), LocationBean.MINLNG, LocationBean.MAXLNG); LocationBean location = new LocationBean(latValue, lngValue); location.setGeoHash(geoHash); return location; } /** * @param binaryStr * @param min * @param max * @return * @Author:lulei * @Description: 返回二進制對應的中間值 */ private double getGeoHashMid(String binaryStr, double min, double max) { if (binaryStr == null || binaryStr.length() < 1) { return (min + max) / 2.0; } if (binaryStr.charAt(0) == '1') { return getGeoHashMid(binaryStr.substring(1), (min + max) / 2.0, max); } else { return getGeoHashMid(binaryStr.substring(1), min, (min + max) / 2.0); } } /** * @param lat * @param lng * @return * @Author:lulei * @Description: 獲取坐標的geo二進制字符串 */ 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: 合并經緯度二進制 */ 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: 將數字轉化為geohash二進制字符串 */ 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 g = new GeoHash(40.221227, 116.24875); String geoHash = g.getGeoHashBase32(); System.out.println(geoHash); LocationBean bean = g.getLocation(geoHash); System.out.println(JsonUtil.parseJson(bean)); System.out.println(new GeoHash(bean.getLat(), bean.getLng()).getGeoHashBase32()); System.out.println(DistanceUtil.getDistance(bean.getLat(), bean.getLng(), bean.getLat() - g.minLat, bean.getLng() - g.minLng)); } } |
以上就是本文的詳細內容，希望對大家的學習有所幫助。
