code: /*
   Copyright 1995-2017 Esri
  
     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.
  
   For additional information, contact:
   Environmental Systems Research Institute, Inc.
   Attn: Contracts Dept
   380 New York Street
   Redlands, California, USA 92373
  
   email: contracts@esri.com
   */
  package com.esri.core.geometry;
  
  import com.esri.core.geometry.ogc.OGCGeometry;
  import com.esri.core.geometry.ogc.OGCPoint;
  import org.junit.Assert;
  import org.junit.Test;
  
  public class TestOGCCentroid {
  	@Test
  	public void testPoint() {
  		assertCentroid("POINT (1 2)", new Point(1, 2));
  		assertEmptyCentroid("POINT EMPTY");
  	}
  
  	@Test
  	public void testLineString() {
  		assertCentroid("LINESTRING (1 1, 2 2, 3 3)", new Point(2, 2));
  		//closed path
  		assertCentroid("LINESTRING (0 0, 1 0, 1 1, 0 1, 0 0)", new Point(0.5, 0.5));
  		//all points coincide
  		assertCentroid("LINESTRING (0 0, 0 0, 0 0, 0 0, 0 0)", new Point(0.0, 0.0));
  		assertEmptyCentroid("LINESTRING EMPTY");
  	}
  
  	@Test
  	public void testPolygon() {
  		assertCentroid("POLYGON ((1 1, 1 4, 4 4, 4 1))'", new Point(2.5, 2.5));
  		assertCentroid("POLYGON ((1 1, 5 1, 3 4))", new Point(3, 2));
  		assertCentroid("POLYGON ((0 0, 0 5, 5 5, 5 0, 0 0), (1 1, 1 2, 2 2, 2 1, 1 1))",
  				new Point(2.5416666666666665, 2.5416666666666665));
  		assertEmptyCentroid("POLYGON EMPTY");
  	}
  
  	@Test
  	public void testMultiPoint() {
  		assertCentroid("MULTIPOINT (1 2, 2 4, 3 6, 4 8)", new Point(2.5, 5));
  		assertEmptyCentroid("MULTIPOINT EMPTY");
  	}
  
  	@Test
  	public void testMultiLineString() {
  		assertCentroid("MULTILINESTRING ((1 1, 5 1), (2 4, 4 4))')))", new Point(3, 2));
  		assertCentroid("MULTILINESTRING ((1 1, 5 1), (2 4, 3 3, 4 4))')))", new Point(3, 2.0355339059327378));
  		assertCentroid("MULTILINESTRING ((0 0, 0 0, 0 0), (1 1, 1 1, 1 1, 1 1))", new Point(0.571428571428571429, 0.571428571428571429));
  		assertEmptyCentroid("MULTILINESTRING EMPTY");
  	}
  
  	@Test
  	public void testMultiPolygon() {
  		assertCentroid("MULTIPOLYGON (((0 0, 1 0, 1 1, 0 1, 0 0)), ((2 2, 3 2, 3 3, 2 3, 2 2)))", new Point(1.5, 1.5));
  		assertCentroid("MULTIPOLYGON (((2 2, 3 2, 3 3, 2 3, 2 2)), ((4 4, 5 4, 5 5, 4 5, 4 4)))", new Point(3.5, 3.5));
  		assertCentroid("MULTIPOLYGON (((1 1, 1 3, 3 3, 3 1)), ((2 4, 2 6, 6 6, 6 4)))",
  				new Point(3.3333333333333335, 4));
  		
  		//hole is same as exterior - compute as polyline
  		assertCentroid("MULTIPOLYGON (((0 0, 1 0, 1 1, 0 1, 0 0), (0 0, 0 1, 1 1, 1 0, 0 0)))", new Point(0.5, 0.5));
  		
  		//polygon is only vertices - compute as multipoint. Note that the closing vertex of the ring is not counted
  		assertCentroid("MULTIPOLYGON (((0 0, 0 0, 0 0), (1 1, 1 1, 1 1, 1 1)))", new Point(0.6, 0.6));
  		
  		// test cases from https://github.com/Esri/geometry-api-java/issues/225
  		assertCentroid(
  				"MULTIPOLYGON (((153.492818 -28.13729, 153.492821 -28.137291, 153.492816 -28.137289, 153.492818 -28.13729)))",
  				new Point(153.49281833333333, -28.13729));
  		assertCentroid(
  				"MULTIPOLYGON (((153.112475 -28.360526, 153.1124759 -28.360527, 153.1124759 -28.360526, 153.112475 -28.360526)))",
  				new Point(153.1124756, -28.360526333333333));
  		assertEmptyCentroid("MULTIPOLYGON EMPTY");
  	}
  
  	private static void assertCentroid(String wkt, Point expectedCentroid) {
  		OGCGeometry geometry = OGCGeometry.fromText(wkt);
  		OGCGeometry centroid = geometry.centroid();
  		Assert.assertEquals(((OGCPoint)centroid).X(), expectedCentroid.getX(), 1e-13);
  		Assert.assertEquals(((OGCPoint)centroid).Y(), expectedCentroid.getY(), 1e-13);
  	}
  
  	private static void assertEmptyCentroid(String wkt) {
  		OGCGeometry geometry = OGCGeometry.fromText(wkt);
  		OGCGeometry centroid = geometry.centroid();
  		Assert.assertEquals(centroid, new OGCPoint(new Point(), geometry.getEsriSpatialReference()));
  	}
  }
  