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copied!<p>Here is a line by line translation of Marcelo's code in PHP, which can probably be cleaned up a bit. Works great! Thanks to Marcelo for doing the hard part.</p> <pre><code>define("MERCATOR_RANGE", 256); function degreesToRadians($deg) { return $deg * (M_PI / 180); } function radiansToDegrees($rad) { return $rad / (M_PI / 180); } function bound($value, $opt_min, $opt_max) { if ($opt_min != null) $value = max($value, $opt_min); if ($opt_max != null) $value = min($value, $opt_max); return $value; } class G_Point { public $x,$y; function G_Point($x=0, $y=0){ $this->x = $x; $this->y = $y; } } class G_LatLng { public $lat,$lng; function G_LatLng($lt, $ln){ $this->lat = $lt; $this->lng = $ln; } } class MercatorProjection { private $pixelOrigin_, $pixelsPerLonDegree_, $pixelsPerLonRadian_; function MercatorProjection() { $this->pixelOrigin_ = new G_Point( MERCATOR_RANGE / 2, MERCATOR_RANGE / 2); $this->pixelsPerLonDegree_ = MERCATOR_RANGE / 360; $this->pixelsPerLonRadian_ = MERCATOR_RANGE / (2 * M_PI); } public function fromLatLngToPoint($latLng, $opt_point=null) { $me = $this; $point = $opt_point ? $opt_point : new G_Point(0,0); $origin = $me->pixelOrigin_; $point->x = $origin->x + $latLng->lng * $me->pixelsPerLonDegree_; // NOTE(appleton): Truncating to 0.9999 effectively limits latitude to // 89.189. This is about a third of a tile past the edge of the world tile. $siny = bound(sin(degreesToRadians($latLng->lat)), -0.9999, 0.9999); $point->y = $origin->y + 0.5 * log((1 + $siny) / (1 - $siny)) * -$me->pixelsPerLonRadian_; return $point; } public function fromPointToLatLng($point) { $me = $this; $origin = $me->pixelOrigin_; $lng = ($point->x - $origin->x) / $me->pixelsPerLonDegree_; $latRadians = ($point->y - $origin->y) / -$me->pixelsPerLonRadian_; $lat = radiansToDegrees(2 * atan(exp($latRadians)) - M_PI / 2); return new G_LatLng($lat, $lng); } //pixelCoordinate = worldCoordinate * pow(2,zoomLevel) } function getCorners($center, $zoom, $mapWidth, $mapHeight){ $scale = pow(2, $zoom); $proj = new MercatorProjection(); $centerPx = $proj->fromLatLngToPoint($center); $SWPoint = new G_Point($centerPx->x-($mapWidth/2)/$scale, $centerPx->y+($mapHeight/2)/$scale); $SWLatLon = $proj->fromPointToLatLng($SWPoint); $NEPoint = new G_Point($centerPx->x+($mapWidth/2)/$scale, $centerPx->y-($mapHeight/2)/$scale); $NELatLon = $proj->fromPointToLatLng($NEPoint); return array( 'N' => $NELatLon->lat, 'E' => $NELatLon->lng, 'S' => $SWLatLon->lat, 'W' => $SWLatLon->lng, ); } </code></pre> <p>Usage:</p> <pre><code>$centerLat = 49.141404; $centerLon = -121.960988; $zoom = 10; $mapWidth = 640; $mapHeight = 640; $centerPoint = new G_LatLng($centerLat, $centerLon); $corners = getCorners($centerPoint, $zoom, $mapWidth, $mapHeight); $mapURL = "http://maps.googleapis.com/maps/api/staticmap?center={$centerLat},{$centerLon}&zoom={$zoom}&size={$mapWidth}x{$mapHeight}&scale=2&maptype=roadmap&sensor=false"; </code></pre>

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