org.locationtech.proj4j.proj.NellProjection Maven / Gradle / Ivy

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/*******************************************************************************
 * Copyright 2006, 2017 Jerry Huxtable, Martin Davis
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

/*
 * This file was semi-automatically converted from the public-domain USGS PROJ source.
 */
package org.locationtech.proj4j.proj;

import org.locationtech.proj4j.ProjCoordinate;
import org.locationtech.proj4j.util.ProjectionMath;

public class NellProjection extends Projection {

	private final static int MAX_ITER = 10;
	private final static double LOOP_TOL = 1e-7;

	public ProjCoordinate project(double lplam, double lpphi, ProjCoordinate out) {
		double k, V;
		int i;

		k = 2. * Math.sin(lpphi);
		V = lpphi * lpphi;
		out.y *= 1.00371 + V * (-0.0935382 + V * -0.011412);
		for (i = MAX_ITER; i > 0 ; --i) {
			out.y -= V = (lpphi + Math.sin(lpphi) - k) /
				(1. + Math.cos(lpphi));
			if (Math.abs(V) < LOOP_TOL)
				break;
		}
		out.x = 0.5 * lplam * (1. + Math.cos(lpphi));
		out.y = lpphi;
		return out;
	}

	public ProjCoordinate projectInverse(double xyx, double xyy, ProjCoordinate out) {
		double th, s;

		out.x = 2. * xyx / (1. + Math.cos(xyy));
		out.y = ProjectionMath.asin(0.5 * (xyy + Math.sin(xyy)));
		return out;
	}

	public boolean hasInverse() {
		return true;
	}

	public String toString() {
		return "Nell";
	}

}