GeoHashUtilsTests.java

/*
 * Licensed to ElasticSearch and Shay Banon 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.elasticsearch.test.unit.index.search.geo;

import org.elasticsearch.index.search.geo.GeoHashUtils;
import org.testng.annotations.Test;

import static org.testng.Assert.assertEquals;

/**
 *
 */
public class GeoHashUtilsTests {

    /**
     * Pass condition: lat=42.6, lng=-5.6 should be encoded as "ezs42e44yx96",
     * lat=57.64911 lng=10.40744 should be encoded as "u4pruydqqvj8"
     */
    @Test
    public void testEncode() {
        String hash = GeoHashUtils.encode(42.6, -5.6);
        assertEquals("ezs42e44yx96", hash);

        hash = GeoHashUtils.encode(57.64911, 10.40744);
        assertEquals("u4pruydqqvj8", hash);
    }

    /**
     * Pass condition: lat=52.3738007, lng=4.8909347 should be encoded and then
     * decoded within 0.00001 of the original value
     */
    @Test
    public void testDecodePreciseLongitudeLatitude() {
        String hash = GeoHashUtils.encode(52.3738007, 4.8909347);

        double[] latitudeLongitude = GeoHashUtils.decode(hash);

        assertEquals(52.3738007, latitudeLongitude[0], 0.00001D);
        assertEquals(4.8909347, latitudeLongitude[1], 0.00001D);
    }

    /**
     * Pass condition: lat=84.6, lng=10.5 should be encoded and then decoded
     * within 0.00001 of the original value
     */
    @Test
    public void testDecodeImpreciseLongitudeLatitude() {
        String hash = GeoHashUtils.encode(84.6, 10.5);

        double[] latitudeLongitude = GeoHashUtils.decode(hash);

        assertEquals(84.6, latitudeLongitude[0], 0.00001D);
        assertEquals(10.5, latitudeLongitude[1], 0.00001D);
    }

    /*
    * see https://issues.apache.org/jira/browse/LUCENE-1815 for details
    */

    @Test
    public void testDecodeEncode() {
        String geoHash = "u173zq37x014";
        assertEquals(geoHash, GeoHashUtils.encode(52.3738007, 4.8909347));
        double[] decode = GeoHashUtils.decode(geoHash);
        assertEquals(52.37380061d, decode[0], 0.000001d);
        assertEquals(4.8909343d, decode[1], 0.000001d);

        assertEquals(geoHash, GeoHashUtils.encode(decode[0], decode[1]));

        geoHash = "u173";
        decode = GeoHashUtils.decode("u173");
        geoHash = GeoHashUtils.encode(decode[0], decode[1]);
        assertEquals(decode[0], GeoHashUtils.decode(geoHash)[0], 0.000001d);
        assertEquals(decode[1], GeoHashUtils.decode(geoHash)[1], 0.000001d);
    }
}