Main.java Source code

Introduction

Here is the source code for Main.java

Source

//package com.java2s;
//License from project: Apache License 

import java.awt.Point;
import java.awt.geom.Point2D;

public class Main {
    /**
     * Returns a point that is a google tile reference for the tile containing
     * the lat/lng and at the zoom level.
     */
    public static Point toTileXY(double lat, double lng, int zoom) {
        Point2D normalised = toNormalisedPixelCoords(lat, lng);
        int scale = 1 << zoom;

        // can just truncate to integer, this looses the fractional "pixel offset"
        return new Point((int) (normalised.getX() * scale), (int) (normalised.getY() * scale));
    }

    /**
     * Returns the lat/lng as an "Offset Normalized Mercator" pixel coordinate,
     * this is a coordinate that runs from 0..1 in latitude and longitude with 0,0 being
     * top left. Normalizing means that this routine can be used at any zoom level and
     * then multiplied by a power of two to get actual pixel coordinates.
     */
    public static Point2D toNormalisedPixelCoords(double lat, double lng) {
        // first convert to Mercator projection
        // first convert the lat lon to mercator coordintes.
        if (lng > 180) {
            lng -= 360;
        }

        lng /= 360;
        lng += 0.5;

        lat = 0.5 - ((Math.log(Math.tan((Math.PI / 4) + ((0.5 * Math.PI * lat) / 180))) / Math.PI) / 2.0);

        return new Point2D.Double(lng, lat);
    }
}