wp-gpx-maps/wp-gpx-maps_Utils.php

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2011-12-19 13:27:22 +00:00
<?php
function getPoints($gpxPath,$gpxOffset = 10)
{
$points = array();
$dist=0;
$lastLat=0;
$lastLon=0;
$lastEle=0;
$lastOffset=0;
//Default Offset = 10 mt
if (!($gpxOffset > 0))
{
$gpxOffset = 10;
}
$realGpxPath = substr (__FILE__, 0, strrpos(__FILE__,'/wp-content/')).$gpxPath;
if (file_exists($realGpxPath))
{
$gpx = simplexml_load_file($realGpxPath);
$gpx->registerXPathNamespace('10', 'http://www.topografix.com/GPX/1/0');
$gpx->registerXPathNamespace('11', 'http://www.topografix.com/GPX/1/1');
foreach($gpx->xpath('//trkpt | //10:trkpt | //11:trkpt') as $trkpt){
$lat = $trkpt['lat'];
$lon = $trkpt['lon'];
$ele = $trkpt->ele;
if ($lastLat == 0 && $lastLon == 0)
{
//Base Case
array_push($points, array((float)$lat,(float)$lon,(float)round($ele,1),(float)round($dist,1)));
$lastLat=$lat;
$lastLon=$lon;
$lastEle=$ele;
}
else
{
//Normal Case
$offset = calculateDistance($lat, $lon, $ele,$lastLat, $lastLon, $lastEle);
$dist = $dist + $offset;
if (((float) $offset + (float) $lastOffset) > $gpxOffset)
{
//Bigger Offset -> write coordinate
$lastOffset=0;
array_push($points, array((float)$lat,(float)$lon,(float)round($ele,1),(float)round($dist,1)));
}
else
{
//Smoller Offset -> continue..
$lastOffset= (float) $lastOffset + (float) $offset ;
}
}
$lastLat=$lat;
$lastLon=$lon;
$lastEle=$ele;
}
}
else
{
array_push($points, array((float)0,(float)0,(float)0,(float)0));
}
// riduco l'array a circa 200 punti per non appensantire la pagina(mappa e grafico)!
$count=sizeof($points);
if ($count>200)
{
$f = round($count/200);
if ($f>1)
for($i=$count;$i>0;$i--)
if ($i % $f != 0)
unset($points[$i]);
}
return $points;
}
function toRadians($degrees)
{
return $degrees * 3.1415926535897932385 / 180;
}
function calculateDistance($lat1,$lon1,$ele1,$lat2,$lon2,$ele2)
{
//Distance in meters
$dLat = toRadians((float) $lat2 - (float) $lat1);
$dLng = toRadians((float) $lon2 - (float) $lon1);
$a = (float) ( sin($dLat / 2) * sin($dLat / 2)) + (float) ( cos( toRadians($lat1)) * cos( toRadians($lat2)) * sin($dLng / 2) * sin($dLng / 2) );
$dist = 2 * 3958.75 * atan2(sqrt($a), sqrt(1 - (float) $a));
return sqrt(pow($dist * 1609.00, 2) + pow((float) $lat1 - (float)$lat2, 2));
}
2011-12-14 10:35:25 +00:00
?>