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/*
* Licensed to Elasticsearch under one or more contributor
* license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright
* ownership. Elasticsearch licenses this file to you 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.
*/
package org.apache.lucene.util;
import org.elasticsearch.common.geo.GeoDistance;
import org.elasticsearch.common.unit.DistanceUnit;
import org.elasticsearch.test.ElasticsearchTestCase;
import org.junit.Test;
import static org.hamcrest.number.IsCloseTo.closeTo;
public class SloppyMathTests extends ElasticsearchTestCase {
@Test
public void testAccuracy() {
for (double lat1 = -89; lat1 <= 89; lat1+=1) {
final double lon1 = randomLongitude();
for (double i = -180; i <= 180; i+=1) {
final double lon2 = i;
final double lat2 = randomLatitude();
assertAccurate(lat1, lon1, lat2, lon2);
}
}
}
@Test
public void testSloppyMath() {
assertThat(GeoDistance.SLOPPY_ARC.calculate(-46.645, -171.057, -46.644, -171.058, DistanceUnit.METERS), closeTo(134.87709, maxError(134.87709)));
assertThat(GeoDistance.SLOPPY_ARC.calculate(-77.912, -81.173, -77.912, -81.171, DistanceUnit.METERS), closeTo(46.57161, maxError(46.57161)));
assertThat(GeoDistance.SLOPPY_ARC.calculate(65.75, -20.708, 65.75, -20.709, DistanceUnit.METERS), closeTo(45.66996, maxError(45.66996)));
assertThat(GeoDistance.SLOPPY_ARC.calculate(-86.9, 53.738, -86.9, 53.741, DistanceUnit.METERS), closeTo(18.03998, maxError(18.03998)));
assertThat(GeoDistance.SLOPPY_ARC.calculate(89.041, 115.93, 89.04, 115.946, DistanceUnit.METERS), closeTo(115.11711, maxError(115.11711)));
testSloppyMath(DistanceUnit.METERS, 0.01, 5, 45, 90);
testSloppyMath(DistanceUnit.KILOMETERS, 0.01, 5, 45, 90);
testSloppyMath(DistanceUnit.INCH, 0.01, 5, 45, 90);
testSloppyMath(DistanceUnit.MILES, 0.01, 5, 45, 90);
}
private static double maxError(double distance) {
return distance / 1000.0;
}
private void testSloppyMath(DistanceUnit unit, double...deltaDeg) {
final double lat1 = randomLatitude();
final double lon1 = randomLongitude();
logger.info("testing SloppyMath with {} at \"{}, {}\"", unit, lat1, lon1);
for (int test = 0; test < deltaDeg.length; test++) {
for (int i = 0; i < 100; i++) {
// crop pole areas, sine we now there the function
// is not accurate around lat(89°, 90°) and lat(-90°, -89°)
final double lat2 = Math.max(-89.0, Math.min(+89.0, lat1 + (randomDouble() - 0.5) * 2 * deltaDeg[test]));
final double lon2 = lon1 + (randomDouble() - 0.5) * 2 * deltaDeg[test];
final double accurate = GeoDistance.ARC.calculate(lat1, lon1, lat2, lon2, unit);
final double dist = GeoDistance.SLOPPY_ARC.calculate(lat1, lon1, lat2, lon2, unit);
assertThat("distance between("+lat1+", "+lon1+") and ("+lat2+", "+lon2+"))", dist, closeTo(accurate, maxError(accurate)));
}
}
}
private static void assertAccurate(double lat1, double lon1, double lat2, double lon2) {
double accurate = GeoDistance.ARC.calculate(lat1, lon1, lat2, lon2, DistanceUnit.METERS);
double sloppy = GeoDistance.SLOPPY_ARC.calculate(lat1, lon1, lat2, lon2, DistanceUnit.METERS);
assertThat("distance between("+lat1+", "+lon1+") and ("+lat2+", "+lon2+"))", sloppy, closeTo(accurate, maxError(accurate)));
}
private static final double randomLatitude() {
// crop pole areas, sine we now there the function
// is not accurate around lat(89°, 90°) and lat(-90°, -89°)
return (getRandom().nextDouble() - 0.5) * 178.0;
}
private static final double randomLongitude() {
return (getRandom().nextDouble() - 0.5) * 360.0;
}
}
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