mercatorsector.java

world wind java sdk 源码

/*
Copyright (C) 2001, 2009 United States Government
as represented by the Administrator of the
National Aeronautics and Space Administration.
All Rights Reserved.
*/
package gov.nasa.worldwind.layers.Mercator;


import gov.nasa.worldwind.geom.Angle;
import gov.nasa.worldwind.geom.Sector;

public class MercatorSector extends Sector
{
	private double minLatPercent, maxLatPercent;

	public MercatorSector(double minLatPercent, double maxLatPercent,
			Angle minLongitude, Angle maxLongitude)
	{
		super(gudermannian(minLatPercent), gudermannian(maxLatPercent),
				minLongitude, maxLongitude);
		this.minLatPercent = minLatPercent;
		this.maxLatPercent = maxLatPercent;

	}

	public static MercatorSector fromDegrees(double minLatPercent,
			double maxLatPercent, double minLongitude, double maxLongitude)
	{
		return new MercatorSector(minLatPercent, maxLatPercent, Angle
				.fromDegrees(minLongitude), Angle.fromDegrees(maxLongitude));
	}

	public static MercatorSector fromSector(Sector sector)
	{
		return new MercatorSector(gudermannianInverse(sector.getMinLatitude()),
				gudermannianInverse(sector.getMaxLatitude()), new Angle(sector
						.getMinLongitude()),
				new Angle(sector.getMaxLongitude()));
	}

	public static double gudermannianInverse(Angle latitude)
	{
		return Math.log(Math.tan(Math.PI / 4.0 + latitude.radians / 2.0))
				/ Math.PI;
	}

	public static Angle gudermannian(double percent)
	{
		return Angle.fromRadians(Math.atan(Math.sinh(percent * Math.PI)));
	}

	public double getMinLatPercent()
	{
		return minLatPercent;
	}

	public double getMaxLatPercent()
	{
		return maxLatPercent;
	}
}