Add more functions

JBlond · Dec 13, 2022 · 7895342 · 7895342
1 parent 45c097f
commit 7895342
Show file tree

Hide file tree

Showing 5 changed files with 237 additions and 14 deletions.
diff --git a/README.md b/README.md
@@ -17,14 +17,37 @@ composer require jblond/math-functions
 
 ## Geo distance
 
-Calculates the great-circle distance between two points, 
-with the Vincenty formula.
+Calculates the distance between two points. Choose your function.
 
-- get function
+- vincenty function
   - Parameters
     - float $latitudeFrom Latitude of start point in [deg decimal]
     - float $longitudeFrom Longitude of start point in [deg decimal]
     - float $latitudeTo Latitude of target point in [deg decimal]
     - float $longitudeTo Longitude of target point in [deg decimal]
     - float $earthRadius Mean earth radius in [m]
     - OPTIONAL float|int Distance between points in [m] (same as earthRadius) default: 6371000 meters
+- haversine function
+  - Parameters
+    - float $latitudeFrom Latitude of start point in [deg decimal]
+    - float $longitudeFrom Longitude of start point in [deg decimal]
+    - float $latitudeTo Latitude of target point in [deg decimal]
+    - float $longitudeTo Longitude of target point in [deg decimal]
+- greatCircle
+  - Parameters
+    - float $latitudeFrom Latitude of start point in [deg decimal]
+    - float $longitudeFrom Longitude of start point in [deg decimal]
+    - float $latitudeTo Latitude of target point in [deg decimal]
+    - float $longitudeTo Longitude of target point in [deg decimal]
+- equirectangularApproximation
+  - Parameters
+    - float $latitudeFrom Latitude of start point in [deg decimal]
+    - float $longitudeFrom Longitude of start point in [deg decimal]
+    - float $latitudeTo Latitude of target point in [deg decimal]
+    - float $longitudeTo Longitude of target point in [deg decimal]
+- cosineLaw
+  - Parameters
+    - float $latitudeFrom Latitude of start point in [deg decimal]
+    - float $longitudeFrom Longitude of start point in [deg decimal]
+    - float $latitudeTo Latitude of target point in [deg decimal]
+    - float $longitudeTo Longitude of target point in [deg decimal]
diff --git a/composer.json b/composer.json
@@ -31,6 +31,7 @@
     "classmap-authoritative": true
   },
   "scripts": {
-    "phpunit": "phpunit ./tests/"
+    "phpunit": "phpunit ./tests/",
+    "test": "phpunit --colors=always --testdox"
   }
 }
diff --git a/phpunit.xml b/phpunit.xml
@@ -0,0 +1,17 @@
+<?xml version="1.0"?>
+<phpunit
+        xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+        colors="true"
+        bootstrap="vendor/autoload.php"
+        xsi:noNamespaceSchemaLocation="https://schema.phpunit.de/9.5/phpunit.xsd">
+    <coverage includeUncoveredFiles="true">
+        <include>
+            <directory>./src</directory>
+        </include>
+    </coverage>
+    <testsuites>
+        <testsuite name="unit">
+            <directory>tests</directory>
+        </testsuite>
+    </testsuites>
+</phpunit>
diff --git a/src/GeoDistance.php b/src/GeoDistance.php
@@ -41,14 +41,22 @@ public function vincenty(
     }
 
     /**
-     * @param $lat1
-     * @param $lon1
-     * @param $lat2
-     * @param $lon2
+     * The Haversine formula is a simple and efficient way to calculate the distance between two points on the
+     * Earth's surface. It is often used in navigation and geolocation applications.
+     * However, it does not account for the Earth's elliptical shape.
+     *
+     * @param float $lat1
+     * @param float $lon1
+     * @param float $lat2
+     * @param float $lon2
      * @return float|int
      */
-    function haversine($lat1, $lon1, $lat2, $lon2)
-    {
+    public function haversine(
+        float $lat1,
+        float $lon1,
+        float $lat2,
+        float $lon2
+    ) {
         // convert latitude and longitude to radians
         $lat1 = deg2rad($lat1);
         $lon1 = deg2rad($lon1);
@@ -62,7 +70,97 @@ function haversine($lat1, $lon1, $lat2, $lon2)
         // apply the Haversine formula
         $a = sin($lat_diff / 2) * sin($lat_diff / 2) + cos($lat1) * cos($lat2) * sin($lon_diff / 2) * sin($lon_diff / 2);
         $c = 2 * atan2(sqrt($a), sqrt(1 - $a));
-        return 6371 * $c; // 6371 is the approximate radius of the Earth in kilometers
+        return 6371000 * $c; // 6371000 is the approximate radius of the Earth in meters
+    }
+
+    /**
+     * The Great Circle formula is similar to the Haversine formula, but it uses a slightly different formula
+     * to calculate the central angle between the two points. Both methods are based on the assumption
+     * that the Earth is a perfect sphere, so they are not as accurate as the Vincenty formula for distances
+     * over a few hundred kilometers. However, the Great Circle formula is simpler and faster to compute
+     * than the Vincenty formula, so it may be a good choice for applications that do not require high accuracy.
+     *
+     * @param float $lat1
+     * @param float $lon1
+     * @param float $lat2
+     * @param float $lon2
+     * @return float|int
+     */
+    public function greatCircle(
+        float $lat1,
+        float $lon1,
+        float $lat2,
+        float $lon2
+    ) {
+        // convert latitude and longitude to radians
+        $lat1 = deg2rad($lat1);
+        $lon1 = deg2rad($lon1);
+        $lat2 = deg2rad($lat2);
+        $lon2 = deg2rad($lon2);
+
+        // calculate the differences
+        $lat_diff = $lat2 - $lat1;
+        $lon_diff = $lon2 - $lon1;
+
+        // apply the Great Circle formula
+        $a = sin($lat_diff / 2) * sin($lat_diff / 2) + cos($lat1) * cos($lat2) * sin($lon_diff / 2) * sin($lon_diff / 2);
+        $c = 2 * atan2(sqrt($a), sqrt(1 - $a));
+        return 6371000 * $c; // 6371000 is the approximate radius of the Earth in meters
+    }
+
+    /**
+     * This would return the distance in kilometers between the two points with the given latitude and longitude.
+     * The equirectangular approximation is a simple formula that is fast to compute,
+     * but it is not very accurate for distances over a few hundred kilometers. For more accurate calculations,
+     * you should use a different method, such as the Haversine formula.
+     *
+     * @param float $lat1
+     * @param float $lon1
+     * @param float $lat2
+     * @param float $lon2
+     * @return float|int
+     */
+    public  function equirectangularApproximation(
+        float $lat1,
+        float $lon1,
+        float $lat2,
+        float $lon2
+    ) {
+        // convert latitude and longitude to radians
+        $lat1 = deg2rad($lat1);
+        $lon1 = deg2rad($lon1);
+        $lat2 = deg2rad($lat2);
+        $lon2 = deg2rad($lon2);
+
+        // apply the formula
+        $x = ($lon2 - $lon1) * cos(($lat1 + $lat2) / 2);
+        $y = $lat2 - $lat1;
+        return sqrt($x * $x + $y * $y) * 6371000; // 6371000 is the radius of the Earth in meters
     }
 
+    /**
+     * @param float $lat1
+     * @param float $lon1
+     * @param float $lat2
+     * @param float $lon2
+     * @return float|int
+     */
+    public function cosineLaw(
+        float $lat1,
+        float $lon1,
+        float $lat2,
+        float $lon2
+    ) {
+
+        // convert latitude and longitude to radians
+        $lat1 = deg2rad($lat1);
+        $lon1 = deg2rad($lon1);
+        $lat2 = deg2rad($lat2);
+        $lon2 = deg2rad($lon2);
+
+        // apply the formula
+        $cos_theta = sin($lat1) * sin($lat2) + cos($lat1) * cos($lat2) * cos($lon2 - $lon1);
+        $theta = acos($cos_theta);
+        return $theta * 6371000; // 6371000 is the radius of the Earth in meters
+    }
 }
diff --git a/tests/math/GeoDistanceTest.php b/tests/math/GeoDistanceTest.php
@@ -14,7 +14,7 @@ class GeoDistanceTest extends TestCase
      * Should be like https://www.luftlinie.org/Hamburg,DEU/M%C3%BCnchen,Bayern,DEU
      * @return void
      */
-    public function testGet(): void
+    public function testVincenty(): void
     {
         $distance = new GeoDistance();
         $this->assertEquals(
@@ -50,7 +50,7 @@ public function testHaversineDistance(): void
     {
         $distance = new GeoDistance();
         $this->assertEquals(
-            612.3947203510587,
+            612394.7203510588,
             $distance->haversine(
             // Hamburg
                 53.553406,
@@ -62,7 +62,7 @@ public function testHaversineDistance(): void
         );
         // https://www.luftlinie.org/Hamburg,DEU/Los-Angeles,CA,USA
         $this->assertEquals(
-            9075.31474469208,
+            9075314.74469208,
             $distance->haversine(
             // Hamburg
                 53.553406,
@@ -72,6 +72,90 @@ public function testHaversineDistance(): void
                 -118.243680
             )
         );
+    }
+
+    public function testGreatCircle(): void
+    {
+        $distance = new GeoDistance();
+        $this->assertEquals(
+            612394.7203510588,
+            $distance->greatCircle(
+            // Hamburg
+                53.553406,
+                9.992196,
+                // munich
+                48.137108,
+                11.575382
+            )
+        );
+        // https://www.luftlinie.org/Hamburg,DEU/Los-Angeles,CA,USA
+        $this->assertEquals(
+            9075314.74469208,
+            $distance->greatCircle(
+            // Hamburg
+                53.553406,
+                9.992196,
+                // Los Angeles
+                34.052230,
+                -118.243680
+            )
+        );
+    }
+
+    public function testEquirectangularApproximation(): void
+    {
+        $distance = new GeoDistance();
+        $this->assertEquals(
+            612436.6348023742,
+            $distance->equirectangularApproximation(
+            // Hamburg
+                53.553406,
+                9.992196,
+                // munich
+                48.137108,
+                11.575382
+            )
+        );
+        // https://www.luftlinie.org/Hamburg,DEU/Los-Angeles,CA,USA
+        $this->assertEquals(
+            // 9075.31474469208 is the true value. Equirectangular Approximation is no very accurate
+            10517193.640868774,
+            $distance->equirectangularApproximation(
+            // Hamburg
+                53.553406,
+                9.992196,
+                // Los Angeles
+                34.052230,
+                -118.243680
+            )
+        );
+    }
 
+    public function testCosineLaw(): void
+    {
+        $distance = new GeoDistance();
+        $this->assertEquals(
+            612394.7203510538,
+            $distance->cosineLaw(
+            // Hamburg
+                53.553406,
+                9.992196,
+                // munich
+                48.137108,
+                11.575382
+            )
+        );
+        // https://www.luftlinie.org/Hamburg,DEU/Los-Angeles,CA,USA
+        $this->assertEquals(
+            9075314.74469208,
+            $distance->cosineLaw(
+            // Hamburg
+                53.553406,
+                9.992196,
+                // Los Angeles
+                34.052230,
+                -118.243680
+            )
+        );
     }
 }