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88564339 AS |
1 | <?php |
2 | /** | |
3 | * libgpx.php | |
4 | * | |
5 | * Copyright 2018 Andy Street <andy@street.me.uk> | |
6 | * | |
7 | * This program is free software; you can redistribute it and/or modify | |
8 | * it under the terms of the GNU General Public License as published by | |
9 | * the Free Software Foundation; either version 2 of the License, or | |
10 | * (at your option) any later version. | |
11 | * | |
12 | * This program is distributed in the hope that it will be useful, | |
13 | * but WITHOUT ANY WARRANTY; without even the implied warranty of | |
14 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
15 | * GNU General Public License for more details. | |
16 | * | |
17 | * You should have received a copy of the GNU General Public License | |
18 | * along with this program; if not, write to the Free Software | |
19 | * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, | |
20 | * MA 02110-1301, USA. | |
21 | * | |
22 | * | |
23 | */ | |
24 | ||
25 | namespace libgpx; | |
26 | ||
27 | use \DateTimeZone; | |
28 | use \RuntimeException; | |
29 | ||
30 | /** | |
31 | * Constants and miscellaneous functions for the libgpx library. | |
32 | * | |
33 | * @static | |
34 | * @author Andy Street <andy@street.me.uk> | |
35 | */ | |
36 | final class libGPX | |
37 | { | |
38 | ||
39 | /** | |
40 | * The XML namespace for GPX 1.0. | |
41 | */ | |
42 | const NAMESPACE_GPX_1_0 = 'http://www.topografix.com/GPX/1/0'; | |
43 | ||
44 | /** | |
45 | * The XML namespace for GPX 1.1. | |
46 | */ | |
47 | const NAMESPACE_GPX_1_1 = 'http://www.topografix.com/GPX/1/1'; | |
48 | ||
49 | /** | |
50 | * The XML namespace for XML Schema. | |
51 | */ | |
52 | const NAMESPACE_XMLSCHEMA = 'http://www.w3.org/2001/XMLSchema-instance'; | |
53 | ||
54 | /** | |
55 | * The URL of the schema document for GPX 1.0. | |
56 | */ | |
57 | const SCHEMA_GPX_1_0 = 'http://www.topografix.com/GPX/1/0/gpx.xsd'; | |
58 | ||
59 | /** | |
60 | * The URL of the schema document for GPX 1.1. | |
61 | */ | |
62 | const SCHEMA_GPX_1_1 = 'http://www.topografix.com/GPX/1/1/gpx.xsd'; | |
63 | ||
64 | /** | |
65 | * If libgpx::init() has been completed successfully. | |
66 | * | |
67 | * @var boolean | |
68 | */ | |
69 | private static $initialized = false; | |
70 | ||
71 | /** | |
72 | * Empty constructor - class is static. | |
73 | */ | |
74 | private function __construct() {} | |
75 | ||
76 | /** | |
77 | * Check if the system has the required dependencies. | |
78 | * | |
79 | * @param boolean $throw If true, throw an exception when dependencies are unmet. | |
80 | * @return boolean If all dependencies are met. | |
81 | * @throws RuntimeException | |
82 | */ | |
83 | public static function checkDependencies($throw = false) | |
84 | { | |
85 | // Define dependencies | |
86 | $php_version = '7.0.0'; | |
87 | $modules = ['xmlreader', 'xmlwriter']; | |
88 | ||
89 | // Check for PHP | |
90 | if (version_compare(PHP_VERSION, $php_version) < 0) { | |
91 | if ($throw) | |
92 | throw new RuntimeException( | |
93 | sprintf('PHP version %s required.', $php_version) | |
94 | ); | |
95 | else | |
96 | return false; | |
97 | } | |
98 | ||
99 | // Check for modules | |
100 | foreach ($modules as $module) { | |
101 | if (!extension_loaded($module)) { | |
102 | if ($throw) | |
103 | throw new RuntimeException(sprintf( | |
104 | 'PHP module "%s" required but not installed.', | |
105 | $module | |
106 | )); | |
107 | else | |
108 | return false; | |
109 | } | |
110 | } | |
111 | ||
112 | return true; | |
113 | } | |
114 | ||
115 | /** | |
116 | * Ensure that dependencies are met and an autoloader is registered. | |
117 | * | |
118 | * @return void | |
119 | * @throws RuntimeException If the dependencies are not met. | |
120 | */ | |
121 | public static function init() | |
122 | { | |
123 | if (self::$initialized) return; | |
124 | self::checkDependencies(true); | |
125 | spl_autoload_register( | |
126 | function ($class) { | |
127 | if (strncmp($class, 'libgpx\\', 7) !== 0) return; | |
128 | $class = strtolower(substr($class, 7)); | |
129 | $filename = __DIR__ . DIRECTORY_SEPARATOR . $class . '.php'; | |
130 | if (is_readable($filename)) { | |
131 | include $filename; | |
132 | } | |
133 | } | |
134 | ); | |
135 | self::$initialized = true; | |
136 | } | |
137 | ||
d23d8f6f AS |
138 | /** |
139 | * Measure the distance between two points. | |
140 | * | |
141 | * Haversine formula, great circle distance. | |
142 | * | |
143 | * @param float $lat1 The latitude of the first point. | |
144 | * @param float $lon1 The longitude of the first point. | |
145 | * @param float $lat2 The latitude of the second point. | |
146 | * @param float $lon2 The longitude of the second point. | |
147 | * @return float The distance in meters. | |
148 | */ | |
149 | public static function distance( | |
150 | float $lat1, | |
151 | float $lon1, | |
152 | float $lat2, | |
153 | float $lon2 | |
154 | ) { | |
155 | $deg2rad = pi() / 180; | |
156 | $r = 6371000; // Radius of the Earth in meters | |
157 | $dlat = ($lat2 - $lat1) * $deg2rad; | |
158 | $dlon = ($lon2 - $lon1) * $deg2rad; | |
159 | $a = | |
160 | sin($dlat / 2) * sin($dlat / 2) + | |
161 | cos($lat1 * $deg2rad) * cos($lat2 * $deg2rad) * | |
162 | sin($dlon / 2) * sin($dlon / 2); | |
163 | $c = 2 * atan2(sqrt($a), sqrt(1-$a)); | |
164 | return $r * $c; | |
165 | } | |
166 | ||
167 | /** | |
168 | * Convert meters in to miles. | |
169 | * | |
170 | * @see https://en.wikipedia.org/wiki/Mile | |
171 | * | |
172 | * @param float $meters A distance in meters. | |
173 | * @return float A distance in miles. | |
174 | */ | |
175 | public static function meters2miles(float $meters) | |
176 | { | |
177 | return $meters / 1609.344; | |
178 | } | |
179 | ||
88564339 | 180 | } |