以下是JavaScript中的函数...从OpenLayers中提取
function toMercator (lon, lat) {
var x = lon * 20037508.34 / 180;
var y = Math.log(Math.tan((90 + lat) * Math.PI / 360)) / (Math.PI / 180);
y = y * 20037508.34 / 180;
return [x, y];
}
function inverseMercator (x, y) {
var lon = (x / 20037508.34) * 180;
var lat = (y / 20037508.34) * 180;
lat = 180/Math.PI * (2 * Math.atan(Math.exp(lat * Math.PI / 180)) - Math.PI / 2);
return [lon, lat];
}
Java中的瓦片实用程序代码(对于Google地图开发人员来说是一个很好的资源)
GeoTools拥有转换到和从几乎任何你能想象到的坐标系的代码,其中也包括Google地图的。它也是开源的。然而,需要指出的是,GeoTools是一个庞大的库,因此如果你正在寻找某些小型、快速且易于使用的东西,那么这可能不是一个好选择。
然而,如果你还要进行其他GIS/坐标转换等操作,我强烈推荐使用它。
如果你使用GeoTools或类似工具,你可能也会对知道Google地图的坐标系统叫做EPSG 3785感兴趣。
$lon = ($lon * 20037508.34) / 180;
$lat = log(tan((90 + $lat) * M_PI / 360)) / (M_PI / 180);
$lat = $lat * 20037508.34 / 180;
来自Mercator:
$lon = ($lon / 20037508.34) * 180;
$lat = ($lat / 20037508.34) * 180;
$lat = 180/M_PI * (2 * atan(exp($lat * M_PI / 180)) - M_PI / 2);
/*
* Utility functions to transform between wgs84 and google projection coordinates
* Derived from openmap http://openmap.bbn.com/
*/
public class MercatorTransform {
public final static double NORTH_POLE = 90.0;
public final static double SOUTH_POLE = -NORTH_POLE;
public final static double DATELINE = 180.0;
public final static double LON_RANGE = 360.0;
final public static transient double wgs84_earthEquatorialRadiusMeters_D = 6378137.0;
private static double latfac = wgs84_earthEquatorialRadiusMeters_D;
private static double lonfac = wgs84_earthEquatorialRadiusMeters_D;
final public static transient double HALF_PI_D = Math.PI / 2.0d;
/**
* Returns google projection coordinates from wgs84 lat,long coordinates
*/
public static double[] forward(double lat, double lon) {
lat = normalizeLatitude(lat);
lon = wrapLongitude(lon);
double latrad = Math.toRadians(lat);
double lonrad = Math.toRadians(lon);
double lat_m = latfac * Math.log(Math.tan(((latrad + HALF_PI_D) / 2d)));
double lon_m = lonfac * lonrad;
double[] x = { lon_m, lat_m };
return x;
}
/**
* Returns wgs84 lat,long coordinates from google projection coordinates
*/
public static float[] inverse(float lon_m, float lat_m) {
double latrad = (2d * Math.atan(Math.exp(lat_m / latfac))) - HALF_PI_D;
double lonrad = lon_m / lonfac;
double lat = Math.toDegrees(latrad);
double lon = Math.toDegrees(lonrad);
lat = normalizeLatitude(lat);
lon = wrapLongitude(lon);
float[] x = { (float) lat, (float) lon };
return x;
}
private static double wrapLongitude(double lon) {
if ((lon < -DATELINE) || (lon > DATELINE)) {
lon += DATELINE;
lon = lon % LON_RANGE;
lon = (lon < 0) ? DATELINE + lon : -DATELINE + lon;
}
return lon;
}
private static double normalizeLatitude(double lat) {
if (lat > NORTH_POLE) {
lat = NORTH_POLE;
}
if (lat < SOUTH_POLE) {
lat = SOUTH_POLE;
}
return lat;
}
}