diff --git a/inc/converter.php b/inc/converter.php
index 9530ba9..fd3f356 100644
--- a/inc/converter.php
+++ b/inc/converter.php
@@ -108,7 +108,8 @@ class GeoJson extends Geo {
 	
 	const EXT = '.geojson';
 	const MAX_FILESIZE = 2; //MB
-	const MAX_DEVIATION = 0.1; //10%
+	const MAX_DEVIATION_FLAT = 0.1; //10%
+	const MAX_DEVIATION_ELEV = 0.1; //20%
 	
 	public function __construct($sFileName) {
 		parent::__construct($sFileName);
@@ -136,6 +137,9 @@ class GeoJson extends Geo {
 	public function buildTracks($asTracks, $bSimplify=false) {
 		$this->addNotice('Creating '.($bSimplify?'Simplified ':'').'GeoJson Tracks');
 		
+		$iGlobalInvalidPointCount = 0;
+		$iGlobalPointCount = 0;
+		
 		$this->asTracks = array();
 		foreach($asTracks as $asTrackProps) {
 			
@@ -178,40 +182,55 @@ class GeoJson extends Geo {
 			$asTrackPoints = $asTrackProps['points'];
 			$iPointCount = count($asTrackPoints);
 			$iInvalidPointCount = 0;
+			$asPrevPoint = array();
 			foreach($asTrackPoints as $iIndex=>$asPoint) {
-				if($bSimplify && $iIndex > 0 && $iIndex < ($iPointCount - 1)) {
-					if(!$this->isPointValid($asTrackPoints[$iIndex - 1], $asPoint, $asTrackPoints[$iIndex + 1])) {
+				$asNextPoint = ($iIndex < ($iPointCount - 1))?$asTrackPoints[$iIndex + 1]:array();
+				if($bSimplify && !empty($asPrevPoint) && !empty($asNextPoint)) {
+					if(!$this->isPointValid($asPrevPoint, $asPoint, $asNextPoint)) {
 						$iInvalidPointCount++;
 						continue;
 					}
 				}
 				$asTrack['geometry']['coordinates'][] = array_values($asPoint);
+				$asPrevPoint = $asPoint;
 			}
 			$this->asTracks[] = $asTrack;
 			
+			$iGlobalInvalidPointCount += $iInvalidPointCount;
+			$iGlobalPointCount += $iPointCount;
 			if($iInvalidPointCount > 0) $this->addNotice('Removing '.$iInvalidPointCount.'/'.$iPointCount.' points ('.round($iInvalidPointCount / $iPointCount * 100, 1).'%) from '.$asTrackProps['name']);
 		}
+		
+		if($bSimplify) $this->addNotice('Total: '.$iGlobalInvalidPointCount.'/'.$iGlobalPointCount.' points removed ('.round($iGlobalInvalidPointCount / $iGlobalPointCount * 100, 1).'%)');
 	}
 	
 	private function isPointValid($asPointA, $asPointO, $asPointB) {
 		/*	A----O	   Calculate angle AO^OB
-				  \	   If angle is within [Pi - 10%; Pi + 10%], O can be discarded
-				   \   O is valid otherwise
-					B
-					                   -> ->     ->     ->	
-		Law of Cosines: angle = arccos(OA.OB / ||OA||.||OB||)
-		*/
+		 *        \	   If angle is within [Pi - 10%; Pi + 10%], O can be discarded
+		 *         \   O is valid otherwise
+		 *          B
+		 */
+		
+		//Path Turn Check                         -> ->     ->     ->
+		//Law of Cosines (vector): angle = arccos(OA.OB / ||OA||.||OB||)
 		$fVectorOA = array('lon'=>($asPointA['lon'] - $asPointO['lon']), 'lat'=> ($asPointA['lat'] - $asPointO['lat']));
 		$fVectorOB = array('lon'=>($asPointB['lon'] - $asPointO['lon']), 'lat'=> ($asPointB['lat'] - $asPointO['lat']));
 		
-		$fVectorOAxOB = $fVectorOA['lon'] * $fVectorOB['lon'] + $fVectorOA['lat'] * $fVectorOB['lat'];
-		
 		$fLengthOA = sqrt(pow($asPointA['lon'] - $asPointO['lon'], 2) + pow($asPointA['lat'] - $asPointO['lat'], 2));
 		$fLengthOB = sqrt(pow($asPointO['lon'] - $asPointB['lon'], 2) + pow($asPointO['lat'] - $asPointB['lat'], 2));
 		
+		$fVectorOAxOB = $fVectorOA['lon'] * $fVectorOB['lon'] + $fVectorOA['lat'] * $fVectorOB['lat'];
 		$fAngleAOB = acos($fVectorOAxOB/($fLengthOA * $fLengthOB));
 		
-		return ($fAngleAOB <= (1 - self::MAX_DEVIATION) * M_PI || $fAngleAOB >= (1 + self::MAX_DEVIATION) * M_PI);
+		//Elevation Check
+		//Law of Cosines: angle = arccos((OB² + AO² - AB²) / (2*OB*AO))
+		$fLengthAB = sqrt(pow($asPointB['ele'] - $asPointA['ele'], 2) + pow($fLengthOA + $fLengthOB, 2));
+		$fLengthAO = sqrt(pow($asPointO['ele'] - $asPointA['ele'], 2) + pow($fLengthOA, 2));
+		$fLengthOB = sqrt(pow($asPointB['ele'] - $asPointO['ele'], 2) + pow($fLengthOB, 2));
+		$fAngleAOBElev = acos((pow($fLengthOB, 2) + pow($fLengthAO, 2) - pow($fLengthAB, 2)) / (2 * $fLengthOB * $fLengthAO));
+		
+		return ($fAngleAOB <= (1 - self::MAX_DEVIATION_FLAT) * M_PI || $fAngleAOB >= (1 + self::MAX_DEVIATION_FLAT) * M_PI ||
+				$fAngleAOBElev <= (1 - self::MAX_DEVIATION_ELEV) * M_PI || $fAngleAOBElev >= (1 + self::MAX_DEVIATION_ELEV) * M_PI);
 	}
 	
 	private function buildGeoJson() {
diff --git a/readme.md b/readme.md
index 567f8aa..1ad6fd0 100644
--- a/readme.md
+++ b/readme.md
@@ -8,5 +8,4 @@
 * import/export
 * Reset zoom on image closing (lightbox)
 * Fix fullscreen button on ios
-* Fix lightbox portrait mode: push text under
-* Simplify track when converting gpx to geojson
\ No newline at end of file
+* Fix lightbox portrait mode: push text under
\ No newline at end of file