EDIT

/**

 * Copyright (C) 2020 EDIT

 * European Distributed Institute of Taxonomy

 * http://www.e-taxonomy.eu

 *

 * The contents of this file are subject to the Mozilla Public License Version 1.1

 * See LICENSE.TXT at the top of this package for the full license terms.

 */

package eu.etaxonomy.cdm.ext.geo.kml;

import java.awt.geom.Point2D;

import javax.measure.Quantity;

import javax.measure.Unit;

import javax.measure.UnitConverter;

import javax.measure.quantity.Length;

import org.apache.log4j.Logger;

import org.geotools.data.DataUtilities;

import org.geotools.feature.SchemaException;

import org.geotools.feature.simple.SimpleFeatureBuilder;

import org.geotools.geometry.jts.JTS;

import org.geotools.geometry.jts.JTSFactoryFinder;

import org.geotools.referencing.CRS;

import org.geotools.referencing.GeodeticCalculator;

import org.geotools.referencing.crs.DefaultGeographicCRS;

import org.locationtech.jts.geom.Coordinate;

import org.locationtech.jts.geom.CoordinateSequence;

import org.locationtech.jts.geom.Geometry;

import org.locationtech.jts.geom.GeometryFactory;

import org.locationtech.jts.geom.Point;

import org.locationtech.jts.geom.Polygon;

import org.locationtech.jts.util.GeometricShapeFactory;

import org.opengis.feature.GeometryAttribute;

import org.opengis.feature.simple.SimpleFeature;

import org.opengis.feature.simple.SimpleFeatureType;

import org.opengis.geometry.MismatchedDimensionException;

import org.opengis.referencing.FactoryException;

import org.opengis.referencing.NoSuchAuthorityCodeException;

import org.opengis.referencing.crs.CoordinateReferenceSystem;

import org.opengis.referencing.crs.ProjectedCRS;

import org.opengis.referencing.operation.MathTransform;

import org.opengis.referencing.operation.TransformException;

import si.uom.SI;

import tec.uom.se.quantity.Quantities;

/**

 * See :

 * 

 * https://gis.stackexchange.com/questions/311272/create-dynamic-circle-polygon-from-specific-lat-long-using-geotools

 * https://gis.stackexchange.com/questions/283183/using-geometricshapefactory-to-create-circle-with-radius-in-miles

 * 

 * https://stackoverflow.com/questions/36481651/how-do-i-create-a-circle-with-latitude-longitude-and-radius-with-geotools#36528805

 * 

 * 

 * Another great library for creating shapes is https://github.com/locationtech/spatial4j

 * 

 * @author Andreas Kohlbecker

 * @since Apr 21, 2020

 */

public class GeometryBuilder {

	private final static Logger logger = Logger.getLogger(GeometryBuilder.class);

	public enum CircleMethod {

		circle, simpleCircleSmall, simpleCircle, reprojectedCircle;

	}

	/**

	 * Fails with javax.measure.IncommensurableException: m is not compatible with

	 * deg

	 * 

	 * see

	 * https://gis.stackexchange.com/questions/283183/using-geometricshapefactory-to-create-circle-with-radius-in-miles

	 * 

	 * @param radius

	 * @param latitude

	 * @param longitude

	 * @return

	 * @throws NoSuchAuthorityCodeException

	 * @throws FactoryException

	 */

	public Polygon circle(Double radius, Double latitude, Double longitude)

			throws NoSuchAuthorityCodeException, FactoryException {

		Quantity<Length> radiusMeter = Quantities.getQuantity(radius, SI.METRE);

		Unit<Length> origUnit = (Unit<Length>) DefaultGeographicCRS.WGS84.getCoordinateSystem().getAxis(0).getUnit(); //// (Unit<Length>)

																														//// ////

																														//// origCRS.getCoordinateSystem().getAxis(0).getUnit();

		GeometricShapeFactory shapeFactory = new GeometricShapeFactory();

		shapeFactory.setNumPoints(32);

		shapeFactory.setCentre(new Coordinate(latitude, longitude));

		shapeFactory.setSize(radiusMeter.to(origUnit).getValue().doubleValue() * 2);

		Polygon circlePolygon = shapeFactory.createCircle();

		circlePolygon.setSRID(4326);

		return circlePolygon;

	}

	/**

	 * Only suitable for small radius (> 1000 m) as the circles are heavily

	 * distorted otherwise.

	 * 

	 * @param radius

	 * @param latitude

	 * @param longitude

	 * @return

	 */

	public Geometry simpleCircleSmall(Double radius, Double latitude, Double longitude) {

		double diameterInMeters = radius * 2.0d;

		GeometricShapeFactory shapeFactory = new GeometricShapeFactory();

		shapeFactory.setNumPoints(64); // adjustable

		shapeFactory.setCentre(new Coordinate(longitude, latitude));

		// Length in meters of 1° of latitude = always 111.32 km

		shapeFactory.setWidth(diameterInMeters / 111320d);

		// Length in meters of 1° of longitude = 40075 km * cos( latitude ) / 360

		shapeFactory.setHeight(diameterInMeters / (40075000 * Math.cos(Math.toRadians(latitude)) / 360));

		Polygon circle = shapeFactory.createEllipse();

		return circle;

	}

	/**

	 * Creates perfect circles which are looking good but might be projected

	 * incorrectly for the resulting map

	 * 

	 * @param distance

	 * @param latitude

	 * @param longitude

	 * @return

	 */

	public Geometry simpleCircle(Quantity<Length> distance, Double latitude, Double longitude) {

		GeometryFactory geometryFactory = JTSFactoryFinder.getGeometryFactory(null);

		CoordinateSequence coordinateSequence = geometryFactory.getCoordinateSequenceFactory()

				.create(new Coordinate[] { new Coordinate(longitude, latitude) });

		Point point = new Point(coordinateSequence, geometryFactory);

		GeodeticCalculator calc = new GeodeticCalculator(DefaultGeographicCRS.WGS84);

		calc.setStartingGeographicPoint(longitude, latitude);

		UnitConverter converter = distance.getUnit().getConverterTo(SI.METRE);

		double d = converter.convert(distance.getValue()).doubleValue();

		calc.setDirection(0.0, d);

		Point2D p2 = calc.getDestinationGeographicPoint();

		calc.setDirection(90.0, d);

		Point2D p3 = calc.getDestinationGeographicPoint();

		double dy = p2.getY() - latitude;

		double dx = p3.getX() - longitude;

		double dist = (dy + dx) / 2.0;

		Polygon p1 = (Polygon) point.buffer(dist);

		return p1;

	}

	/**

	 * This Method should produces the best circles.

	 * 

	 * The code is based on an example published by Ian Turton on stackoverflow:

	 * 

	 * https://stackoverflow.com/questions/36481651/how-do-i-create-a-circle-with-latitude-longitude-and-radius-with-geotools#36528805

	 * 

	 * see https://gist.github.com/ianturton/973563fe5004985ba35a6e2247f7d823 and

	 * https://gitlab.com/snippets/17558

	 * 

	 * @param feature

	 * @param distance

	 * @return

	 */

	public Geometry bufferFeature(SimpleFeature feature, Double radius) {

		// replacment for Measure<Double, Length> distance:

		Quantity<Length> radiusMeter = Quantities.getQuantity(radius, SI.METRE);

		// extract the geometry

		GeometryAttribute gProp = feature.getDefaultGeometryProperty();

		CoordinateReferenceSystem origCRS = gProp.getDescriptor().getCoordinateReferenceSystem();

		Geometry geom = (Geometry) feature.getDefaultGeometry();

		Geometry pGeom = geom;

		MathTransform toTransform, fromTransform = null;

		// reproject the geometry to a local projection

		if (!(origCRS instanceof ProjectedCRS)) {

			double x = geom.getCoordinate().x;

			double y = geom.getCoordinate().y;

			String code = "AUTO:42001," + x + "," + y;

			// System.out.println(code);

			CoordinateReferenceSystem auto;

			try {

				auto = CRS.decode(code);

				toTransform = CRS.findMathTransform(DefaultGeographicCRS.WGS84, auto);

				fromTransform = CRS.findMathTransform(auto, DefaultGeographicCRS.WGS84);

				pGeom = JTS.transform(geom, toTransform);

			} catch (MismatchedDimensionException | TransformException | FactoryException e) {

				logger.error(e);

			}

		}

		// create a buffer around the geometry, assumes the geometry is in the same

		// units as the distance variable.

		Geometry out = pGeom.buffer(radiusMeter.getValue().doubleValue());

		Geometry retGeom = out;

		// reproject the geometry to the original projection

		if (!(origCRS instanceof ProjectedCRS)) {

			try {

				retGeom = JTS.transform(out, fromTransform);

			} catch (MismatchedDimensionException | TransformException e) {

				logger.error(e);

			}

		}

		return retGeom;

	}

	public static SimpleFeature createSimplePointFeature(Double longitude, Double latitude) throws SchemaException {

		SimpleFeatureType schema = DataUtilities.createType("", "Location", "locations:Point:srid=4326,id:Integer" // a

																													// number

																													// attribute

		);

		SimpleFeatureBuilder featureBuilder = new SimpleFeatureBuilder(schema);

		GeometryFactory geometryFactory = new GeometryFactory();

		/* Longitude (= x coord) first ! */

		Point point = geometryFactory.createPoint(new Coordinate(longitude, latitude));

		featureBuilder.add(point);

		SimpleFeature feature = featureBuilder.buildFeature(null);

		return feature;

	}

}