Haversine Java Implementation in Solr, vs PHP implementation

README

Check this question: http://stackoverflow.com/q/8384415/161278

How to run:
Compile Java:
   $ javac Distance.java
Run test:
   $ php DistanceTest.php


The test will print good result, except that TheProblem.json is the data that Solr actually return and it's inconsistent.

Thanks alot!

data.json

[
    {
        "latitude": 31.9481,
        "longitude": 35.9314
    }, {
        "latitude": 31.9494,
        "longitude": 35.923
    }, {
        "latitude": 31.9491,
        "longitude": 35.9298
    }, {
        "latitude": 31.9496,
        "longitude": 35.9264
    }, {
        "latitude": 31.9495,
        "longitude": 35.9308
    }, {
        "latitude": 31.9516,
        "longitude": 35.9346
    }, {
        "latitude": 31.9532,
        "longitude": 35.9135
    }, {
        "latitude": 31.9531,
        "longitude": 35.9116
    }, {
        "latitude": 31.953,
        "longitude": 35.91
    }, {
        "latitude": 31.9395,
        "longitude": 35.8762
    }, {
        "latitude": 31.9573,
        "longitude": 35.9101
    }, {
        "latitude": 31.9484,
        "longitude": 35.8793
    }, {
        "latitude": 31.9494,
        "longitude": 35.8726
    }, {
        "latitude": 31.9499,
        "longitude": 35.8717
    }, {
        "latitude": 31.9694,
        "longitude": 35.8995
    }, {
        "latitude": 31.9607,
        "longitude": 35.8765
    }, {
        "latitude": 31.9565,
        "longitude": 35.8677
    }, {
        "latitude": 31.9584,
        "longitude": 35.8659
    }, {
        "latitude": 31.9753,
        "longitude": 35.8628
    }, {
        "latitude": 31.98,
        "longitude": 35.8368
    }
]

Distance.java

import java.util.Scanner;

public class Distance {

    private double latCenterRad;
    private double lonCenterRad;
    private double latCenterRad_cos;

    public Distance(double latCenter, double lonCenter) {
        this.latCenterRad = latCenter * DistanceUtils.DEGREES_TO_RADIANS;
        this.lonCenterRad = lonCenter * DistanceUtils.DEGREES_TO_RADIANS;
        latCenterRad_cos = Math.cos(latCenterRad);
    }

    public double calculate(double lat, double lon) {
        double latRad = lat * DistanceUtils.DEGREES_TO_RADIANS;
        double lonRad = lon * DistanceUtils.DEGREES_TO_RADIANS;
        double diffX = latCenterRad - latRad;
        double diffY = lonCenterRad - lonRad;
        double hsinX = Math.sin(diffX * 0.5);
        double hsinY = Math.sin(diffY * 0.5);
        double h = hsinX * hsinX
                + (latCenterRad_cos * Math.cos(latRad) * hsinY * hsinY);
        return (DistanceUtils.EARTH_MEAN_DIAMETER * Math.atan2(Math.sqrt(h), Math.sqrt(1 - h)));
    }
    
    public double calculate2(double lat, double lon) {
        double latRad = lat * DistanceUtils.DEGREES_TO_RADIANS;
        double lonRad = lon * DistanceUtils.DEGREES_TO_RADIANS;
        double planetRadius = DistanceUtils.EARTH_MEAN_RADIUS_KM * DistanceUtils.KM_TO_MILES;

        // haversine, specialized to avoid a cos() call on latCenterRad
        double diffX = latCenterRad - latRad;
        double diffY = lonCenterRad - lonRad;
        double hsinX = Math.sin(diffX * 0.5);
        double hsinY = Math.sin(diffY * 0.5);
        double h = hsinX * hsinX
                + (latCenterRad_cos * Math.cos(latRad) * hsinY * hsinY);
        double result = (planetRadius * 2 * Math.atan2(Math.sqrt(h), Math.sqrt(1 - h)));

        // save the results of this calculation
//      lastDistDoc = doc;
//      lastDist = result;

        return result;
    }

    public static void main(String[] args) {
        Scanner s = new Scanner(join(args, " "));

        Distance d = new Distance(s.nextDouble(), s.nextDouble());

        System.out.println(d.calculate(s.nextDouble(), s.nextDouble()));
    }

    private static String join(String[] input, String delimiter) {
        StringBuilder sb = new StringBuilder();
        for (String value : input) {
            sb.append(value);
            sb.append(delimiter);
        }
        int length = sb.length();
        if (length > 0) {
            // Remove the extra delimiter
            sb.setLength(length - delimiter.length());
        }

        return sb.toString();
    }
}

class DistanceUtils {

    public static final double DEGREES_TO_RADIANS = Math.PI / 180.0;
    public static final double EARTH_MEAN_RADIUS_KM = 6371.009;
    public static final double MILES_TO_KM = 1.609344;
    public static final double KM_TO_MILES = 0.621371192;
    public static final double EARTH_MEAN_DIAMETER = DistanceUtils.EARTH_MEAN_RADIUS_KM * 2 * KM_TO_MILES;
}

DistanceTest.php

<?php

require_once '../include.php'; // Just for autoload Zend stuff, you can ignore this and load Zend_Json manually
$center = array(
    'latitude' => 31.909310,
    'longitude' => 35.921612
);

$data = Zend_Json::decode(file_get_contents('data.json'));

echo trim("
Comparing haversine distance algorithms, in PHP vs Java.
Center:
    latitude={$center['latitude']}
    longitude={$center['longitude']}
== Data =="), "\n";


echo join("\t", array(
    'latitude',
    'longitude',
    "php", "\t",
    "java", "\t",
)), "\n";

foreach ($data as $tip) {
    $php = ZendX_Misc::distance($tip['latitude'], $tip['longitude'], $center['latitude'], $center['longitude'], 'M');
    $java = +trim(`java Distance {$tip['latitude']} {$tip['longitude']} {$center['latitude']} {$center['longitude']}`);

    echo join("\t\t", array(
        $tip['latitude'],
        $tip['longitude'],
        $php,
        $java,
    )), "\n";
}

TheProblem.json

[{
    "latitude": 31.94,
    "longitude": 35.8847,
    "haversinDistance": 83.2840804548,
    "solrDistance": 83.2840804548
}, {
    "latitude": 31.9803,
    "longitude": 35.8376,
    "haversinDistance": 83.8028698367,
    "solrDistance": 83.8028698367
}, {
    "latitude": 31.9951,
    "longitude": 35.8135,
    "haversinDistance": 83.8093195134,
    "solrDistance": 83.8093195134
}, {
    "latitude": 31.9494,
    "longitude": 35.9183,
    "haversinDistance": 85.0358851572,
    "solrDistance": 85.0358851572
}, {
    "latitude": 31.9493,
    "longitude": 35.923,
    "haversinDistance": 85.2070886462,
    "solrDistance": 85.2070886462
}, {
    "latitude": 31.9686,
    "longitude": 35.8993,
    "haversinDistance": 85.3604644706,
    "solrDistance": 85.3604644706
}]

ZendX_Misc.php

<?php

/**
 * Class that contains miscellaneous functions
 * All functions were removed except for distance()
 */
class ZendX_Misc {

    public static function distance($latPoint, $lonPoint, $latCenter, $lonCenter, $units = 'M') {
//        $EARTH_MEAN_RADIUS_KM = 6371.009;

        $planetRadius = 6371.009; // KiloMeters


        $latRad = deg2rad($latPoint);
        $lonRad = deg2rad($lonPoint);

        $latCenterRad = deg2rad($latCenter);
        $lonCenterRad = deg2rad($lonCenter);
        // haversine, specialized to avoid a cos() call on latCenterRad
        $diffX = $latCenterRad - $latRad;
        $diffY = $lonCenterRad - $lonRad;
        $hsinX = sin($diffX * 0.5);
        $hsinY = sin($diffY * 0.5);
        $h = ($hsinX * $hsinX) + (cos($latCenterRad) * cos($latRad) * $hsinY * $hsinY);
        $distanceKM = ($planetRadius * 2 * atan2(sqrt($h), sqrt(1 - $h)));


        switch (strtoupper($units)) {
            case 'M':
                $planetRadius = $planetRadius * 0.621371192 /* 1 km = 0.621371192 mile */;
                break;
        }

        switch (strtoupper($units)) {
            case 'M':
                return $distanceKM * 0.621371192 /* 1 km = 0.621371192 mile */;
                break;
            case 'N':
                return $distanceKM / 1.852;
                break;
            default:
                return $distanceKM;
                break;
        }
    }

}