| 1 | <?php |
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| 2 | |
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| 3 | /** |
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| 4 | * gets several positions and returns a clustered array |
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| 5 | * |
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| 6 | * @author Torben Brodt |
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| 7 | * @license GNU General Public License <http://opensource.org/licenses/gpl-3.0.html> |
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| 8 | */ |
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| 9 | class GmapCluster { |
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| 10 | |
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| 11 | const OFFSET = 268435456; |
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| 12 | const RADIUS = 85445659.4471; /* $self::OFFSET / pi() */ |
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| 13 | |
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| 14 | protected $distance; |
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| 15 | protected $zoom; |
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| 16 | |
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| 17 | /** |
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| 18 | * |
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| 19 | * @param $distance Distance in pixel inside which markers will be clustered. |
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| 20 | * @param $zoom Current map zoom level. |
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| 21 | */ |
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| 22 | public function __construct($distance, $zoom) { |
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| 23 | $this->distance = $distance; |
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| 24 | $this->zoom = $zoom; |
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| 25 | } |
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| 26 | |
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| 27 | protected function lonToX($lon) { |
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| 28 | return round(self::OFFSET + self::RADIUS * $lon * pi() / 180); |
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| 29 | } |
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| 30 | |
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| 31 | protected function latToY($lat) { |
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| 32 | return round(self::OFFSET - self::RADIUS * log((1 + sin($lat * pi() / 180)) / (1 - sin($lat * pi() / 180))) / 2); |
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| 33 | } |
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| 34 | |
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| 35 | protected function pixelDistance($lat1, $lon1, $lat2, $lon2, $zoom) { |
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| 36 | $x1 = $this->lonToX($lon1); |
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| 37 | $y1 = $this->latToY($lat1); |
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| 38 | |
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| 39 | $x2 = $this->lonToX($lon2); |
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| 40 | $y2 = $this->latToY($lat2); |
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| 41 | |
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| 42 | return sqrt(pow(($x1-$x2),2) + pow(($y1-$y2),2)) >> (21 - $zoom); |
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| 43 | } |
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| 44 | |
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| 45 | /** |
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| 46 | * Return average center of markers |
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| 47 | * |
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| 48 | * @return object Google_Maps_Coordinate |
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| 49 | */ |
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| 50 | protected function getCluster(array $markers, $return_ids = false) { |
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| 51 | $count = count($markers); |
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| 52 | $ids = array(); |
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| 53 | |
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| 54 | /* Calculate average lat and lon of markers. */ |
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| 55 | $lat_sum = $lon_sum = 0; |
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| 56 | foreach ($markers as $marker) { |
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| 57 | $lat_sum += $marker['lat']; |
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| 58 | $lon_sum += $marker['lon']; |
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| 59 | if($return_ids) { |
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| 60 | $ids[] = $marker['id']; |
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| 61 | } |
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| 62 | } |
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| 63 | $lat_avg = $lat_sum / $count; |
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| 64 | $lon_avg = $lon_sum / $count; |
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| 65 | |
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| 66 | $data = array( |
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| 67 | 'count' => $count, |
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| 68 | 'lat' => $lat_avg, |
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| 69 | 'lon' => $lon_avg |
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| 70 | ); |
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| 71 | if(count($ids)) { |
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| 72 | $data['ids'] = $ids; |
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| 73 | } |
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| 74 | |
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| 75 | return $data; |
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| 76 | } |
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| 77 | |
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| 78 | /** |
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| 79 | * |
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| 80 | * @param $markers Array of lat and lon locations. |
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| 81 | */ |
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| 82 | public function getMarkers(array $markers, $pick = array()) { |
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| 83 | $clustered = array(); |
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| 84 | |
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| 85 | /* Loop until all markers have been compared. */ |
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| 86 | while (count($markers)) { |
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| 87 | $marker = array_pop($markers); |
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| 88 | $cluster = array(); |
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| 89 | |
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| 90 | /* Compare against all markers which are left. */ |
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| 91 | foreach ($markers as $key => $target) { |
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| 92 | $pixels = $this->pixelDistance($marker['lat'], $marker['lon'], $target['lat'], $target['lon'], $this->zoom); |
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| 93 | |
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| 94 | /* If two markers are closer than given distance remove */ |
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| 95 | /* target marker from array and add it to cluster. */ |
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| 96 | if ($this->distance > $pixels) { |
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| 97 | unset($markers[$key]); |
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| 98 | $cluster[] = $target; |
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| 99 | } |
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| 100 | } |
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| 101 | |
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| 102 | /* If a marker has been added to cluster, add also the one */ |
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| 103 | /* we were comparing to and remove the original from array. */ |
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| 104 | if (count($cluster) > 0) { |
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| 105 | $cluster[] = $marker; |
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| 106 | $clustered[] = $this->getCluster($cluster); |
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| 107 | } else { |
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| 108 | $clustered[] = $marker; |
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| 109 | } |
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| 110 | } |
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| 111 | return $clustered; |
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| 112 | } |
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| 113 | |
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| 114 | /** |
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| 115 | * |
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| 116 | * @param $markers Array of lat and lon locations. |
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| 117 | */ |
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| 118 | public function getIDs(array $markers, $lat, $lon) { |
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| 119 | |
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| 120 | /* Loop until all markers have been compared. */ |
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| 121 | while (count($markers)) { |
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| 122 | $marker = array_pop($markers); |
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| 123 | $cluster = array(); |
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| 124 | |
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| 125 | /* Compare against all markers which are left. */ |
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| 126 | foreach ($markers as $key => $target) { |
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| 127 | $pixels = $this->pixelDistance($marker['lat'], $marker['lon'], $target['lat'], $target['lon'], $this->zoom); |
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| 128 | |
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| 129 | /* If two markers are closer than given distance remove */ |
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| 130 | /* target marker from array and add it to cluster. */ |
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| 131 | if ($this->distance > $pixels) { |
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| 132 | unset($markers[$key]); |
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| 133 | $cluster[] = $target; |
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| 134 | } |
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| 135 | } |
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| 136 | |
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| 137 | /* If a marker has been added to cluster, add also the one */ |
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| 138 | /* we were comparing to and remove the original from array. */ |
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| 139 | if (count($cluster) > 0) { |
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| 140 | $cluster[] = $marker; |
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| 141 | $cluster = $this->getCluster($cluster, true); |
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| 142 | if(abs($cluster['lat'] - $lat) < 0.000000001 && abs($cluster['lon'] - $lon) < 0.000000001) { |
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| 143 | return $cluster['ids']; |
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| 144 | } |
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| 145 | } else { |
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| 146 | if(abs($marker['lat'] - $lat) < 0.000000001 && abs($marker['lon'] - $lon) < 0.000000001) { |
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| 147 | return array($marker['id']); |
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| 148 | } |
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| 149 | } |
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| 150 | } |
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| 151 | return null; |
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| 152 | } |
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| 153 | } |
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