Created
December 14, 2011 15:37
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Generate Encoded Polyline Algorithm Format for Google Static Maps API
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<?php | |
//Generate Encoded Polyline Algorithm Format for Google Static Maps API | |
// http://bit.ly/sw3deL (Japanese) | |
// http://bit.ly/tnKt4m (English) | |
function encodeGPolyline($path){ | |
$enc = ""; | |
$old = true; | |
foreach($path as $latlng){ | |
if($old === true){ | |
$enc .= encodeGPolylineNum($latlng[0]). | |
encodeGPolylineNum($latlng[1]); | |
}else{ | |
$enc .= encodeGPolylineNum($latlng[0] - $old[0]). | |
encodeGPolylineNum($latlng[1] - $old[1]); | |
} | |
$old = $latlng; | |
} | |
return $enc; | |
} | |
function encodeGPolylineNum($num){ | |
$fu = false; | |
if($num < 0){ | |
$fu = true; | |
} | |
//STEP2 | |
$num = round($num * 100000); | |
//STEP3 | |
//$num = decbin($num); | |
//STEP4 | |
$num = $num << 1; | |
//STEP5 | |
if($fu){ | |
$num = ~$num; | |
} | |
//STEP6 - STEP7 | |
$num = decbin($num); | |
$n = str_split($num); | |
$num = array(); | |
$nn = ""; | |
for($c=count($n)-1;$c >= 0;$c--){ | |
$nn = $n[$c].$nn; | |
if(strlen($nn) == 5){ | |
array_push($num,$nn); | |
$nn = ""; | |
} | |
} | |
if(strlen($nn)>0){ | |
$nn = str_repeat("0",5 - strlen($nn)).$nn; | |
array_push($num,$nn); | |
} | |
//STEP8 - STEP9 - STEP10 - STEP11 | |
for($c = 0;$c < count($num);$c++){ | |
if($c != count($num)-1){ | |
$num[$c] = chr(bindec($num[$c]) + 32 + 63); | |
}else{ | |
$num[$c] = chr(bindec($num[$c]) + 63); | |
} | |
} | |
return implode("",$num); | |
} | |
//例 | |
echo encodeGPolylineNum(-179.9832104); | |
echo "<br/><br/>"; | |
echo encodeGPolyline( | |
array( | |
array(38.5,-120.2),array(40.7,-120.95),array(43.252,-126.453) | |
) | |
); | |
?> |
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