function computeGeoInfo() {
	
		$changed=0;
		$gotTrack=0;
		foreach ( $this->photos as $photoNum=>$photoInfo) {
			if ($photoInfo['tm']==1) { // 1 -> we have alredy tried to get geotag info but failed
				continue;
			}
			
			if (!$photoInfo['tm']) { // no attemp was made to get GeoInfo
				$imgPath=$this->getPhotoAbsPath($photoNum);
				$gpsData = CLimage::getGPS($imgPath);
				$this->photos[$photoNum]['lat']=$gpsData[0];
				$this->photos[$photoNum]['lon']=$gpsData[1];
				$this->photos[$photoNum]['tm']=$gpsData[2]; // warning tm in local time ...
				$changed=1; // we got at least the tm				
			}
			
			if (!$this->photos[$photoNum]['tm']) { 
				$this->photos[$photoNum]['tm']=1;
				$changed=1;
				continue;
			}
			
			if (!$this->photos[$photoNum]['lat'] && !$this->photos[$photoNum]['lon']) {
				// try to get lat/lon depending on the position in track	
				if (!$gotTrack) {
					//echo "getting track!";	
					$flight=new flight();
					$flight->getFlightFromDB($this->flightID,0); //dont update takeoffs
					list($trackLat,$trackLon,$trackTms,$trackAlt)=$flight->getXYValues(1,1); // get also TM and ALT
					$gotTrack=1;
				}
				
				//correct the tm of the photo that we got from EXIF by subtracking up the timezone offset
				$this->photos[$photoNum]['tm']-=$flight->timezone*3600;
				
				//we will use this to add to every time entry we gto from getXYValues()
				$startTm=strtotime($flight->DATE);
				//echo "Flight start time is ".$flight->DATE." -> ".$startTm;

				$lastTm=$startTm;
				$photoTm=$this->photos[$photoNum]['tm'];
				
				//echo " starttime:$lastTm  photo : $photoTm<BR>".count($trackTms);
				foreach($trackTms as $i=>$tm) {
					$thisTm=$startTm+$tm;
					if ( $photoTm<$thisTm && $photoTm>$lastTm ) {
					
						//echo "found position!!! tm=$thisTm<BR>";
						$this->photos[$photoNum]['lat']=$trackLat[$i];
						$this->photos[$photoNum]['lon']=-$trackLon[$i];
						$this->photos[$photoNum]['alt']=$trackAlt[$i];
						$changed=1;
						break;
					}				
				}				
				
			}
			
			
		}		
		
		if ($changed) {
			$this->putToDB(0); // dont update the flights table
		}
	}