SparkFun KML

SparkKml.php

<?php
  /**
   * Generates KML for use with SparkVisualize
   *
   * @author Todd Treece
   */
  class SparkKml {
    const SFE_LAT = '40.0648970';
    const SFE_LNG = '-105.2099410';

    private $dom;
    private $kml;
    private $document;

    public function __construct($name='') {
      $this->dom = new DOMDocument('1.0', 'UTF-8');
      $this->kml = $this->dom->createElement('kml');
      $this->kml->setAttribute('xmlns','http://earth.google.com/kml/2.1');
      $this->document = $this->dom->createElement('Document');
      $this->document->appendChild($this->dom->createElement('name',htmlentities($name)));
      $shippingcolor = $this->createLineStyle('sfe_shipment',2,1,'FF2835F0','7DFFFFFF');
      $ordercolor = $this->createLineStyle('sfe_order',2,1,'FF4EF028','7DFFFFFF');
      $bluecircle = $this->createCircleStyle('sfe_order_circle',5,'7dff0000');
      $redcircle = $this->createCircleStyle('sfe_shipment_circle',5,'7d0000ff');
      $this->document->appendChild($shippingcolor);
      $this->document->appendChild($ordercolor);
      $this->document->appendChild($bluecircle);
      $this->document->appendChild($redcircle);
      $this->lookAt(self::SFE_LAT,self::SFE_LNG);      
    }

    public function createLine($lat,$lng,$styleid,$name='',$description='') {
      $placemark = $this->dom->createElement('Placemark');
      $placemark->appendChild($this->dom->createElement('name',htmlentities($name)));
      $placemark->appendChild($this->dom->createElement('description',htmlentities(preg_replace('/[^(\x20-\x7F)]*/','',$description))));
      $placemark->appendChild($this->dom->createElement('styleUrl',$styleid));

      $line = $this->dom->createElement('LineString');
      $line->appendChild($this->dom->createElement('tessellate', '1'));
      $line->appendChild($this->dom->createElement('extrude', '0'));
      $line->appendChild($this->dom->createElement('altitudeMode', 'clampToGround'));

      $destination = $lng . ',' . $lat . ',' . '0';
      $sfe = self::SFE_LNG . ',' . self::SFE_LAT . ',' . '0';
      $midarray = $this->getMidpoint(self::SFE_LAT,self::SFE_LNG,$lat,$lng);
      $midalt = $this->getMidpointAltitude(self::SFE_LAT,self::SFE_LNG,$midarray['lat'],$midarray['lng']);
      $midpoint = $midarray['lng'] . ',' . $midarray['lat'] . ',' . $midalt;

      $line->appendChild($this->dom->createElement('coordinates', $destination /*. ' ' . $midpoint */ . ' ' . $sfe));
      $placemark->appendChild($line);
      $this->document->appendChild($placemark);
    }
    
    public function createCircle($lat, $lng, $radius, $style) {
      $placemark = $this->dom->createElement('Placemark');
      $placemark->appendChild($this->dom->createElement('styleUrl',$style));
      $polygon = $this->dom->createElement('Polygon');
      $boundry = $this->dom->createElement('outerBoundaryIs');
      $ring = $this->dom->createElement('LinearRing');
      $ring->appendChild($this->dom->createElement('tessellate', '1'));
      $radius = $radius/500;
      $steps = 40;
      $angle = 0;
      $coordinates = array();
      
      for ($i = 0; $i < $steps; $i++) {
        $coordinates[] = ($lng + $radius * cos($angle)) . ',' .
          ($lat + $radius * sin($angle)) . ',' .
          '0';
        $angle += 6.28 / $steps;
      }
      $coordinates[] = $coordinates[0];
      $ring->appendChild($this->dom->createElement('coordinates',implode(' ',$coordinates)));
      $boundry->appendChild($ring);
      $polygon->appendChild($boundry);
      $placemark->appendChild($polygon);
      $this->document->appendChild($placemark);
    }
    
    
    public function save() {
      $this->kml->appendChild($this->document);
      $this->dom->appendChild($this->kml);
      $this->dom->formatOutput = true;
      return($this->dom->saveXML());
    }
    
    private function createCircleStyle($id,$width,$color) {
      $style = $this->dom->createElement('Style');
      $style->setAttribute('id',$id);

      $linestyle = $this->dom->createElement('LineStyle');
      $linestyle->appendChild($this->dom->createElement('width', $width));
      $style->appendChild($linestyle);

      $polystyle = $this->dom->createElement('PolyStyle');
      $polystyle->appendChild($this->dom->createElement('color', $color));
      $style->appendChild($polystyle);

      return $style;
    }
    
    private function createLineStyle($id,$width,$outerwidth,$color,$outercolor) {
      $style = $this->dom->createElement('Style');
      $style->setAttribute('id',$id);

      $linestyle = $this->dom->createElement('LineStyle');
      $linestyle->appendChild($this->dom->createElement('color', $color));
      $linestyle->appendChild($this->dom->createElement('width', $width));
      $linestyle->appendChild($this->dom->createElement('gx:physicalWidth', floatval($width)));
      $linestyle->appendChild($this->dom->createElement('gx:outerColor', $outercolor));
      $linestyle->appendChild($this->dom->createElement('gx:outerWidth', floatval($outerwidth)));
      $style->appendChild($linestyle);
      
      return $style;
    }

    private function getMidpointAltitude($lat,$lng,$lat2,$lng2) {
      $radius = 6371000; // radius of earth in meters

      //trig functions take radians
      $lat = deg2rad($lat);
      $lng = deg2rad($lng);
      $lat2 = deg2rad($lat2);
      $lng2 = deg2rad($lng2);
      $diffLat = $lat2-$lat;
      $diffLng = $lng2-$lng;
      
      // http://en.wikipedia.org/wiki/Haversine_formula
      $a = sin($diffLat/2) * sin($diffLat/2) +
              cos($lat) * cos($lat2) * 
              sin($diffLng/2) * sin($diffLng/2); 
      $c = 2 * atan2(sqrt($a), sqrt(1-$a)); 
      $distance = $radius * $c;

      return $distance;
    }

    /**
     * Ported from http://www.movable-type.co.uk/scripts/latlong.html#midpoint
     * @return array
     */
    private function getMidpoint($lat,$lng,$lat2,$lng2) {
      //trig functions take radians
      $lat = deg2rad($lat);
      $lng = deg2rad($lng);
      $lat2 = deg2rad($lat2);
      $lng2 = deg2rad($lng2);
      $diffLng = $lng2 - $lng; 

      $x = cos($lat2) * cos($diffLng);
      $y = cos($lat2) * sin($diffLng);
      $midLat = atan2(sin($lat)+sin($lat2), sqrt((cos($lat)+$x)*(cos($lat)+$x) + $y * $y)); 
      $midLng = $lng + atan2($y, cos($lat) + $x);

      $return = array();
      $return['lat'] = rad2deg($midLat);
      $return['lng'] = rad2deg($midLng);

      return $return;
    }

    private function lookAt($lat,$lng,$alt='10000000',$range='500',$tilt='0',$heading='0') {
      $look = $this->dom->createElement('LookAt');
      $look->appendChild($this->dom->createElement('longitude',$lng));
      $look->appendChild($this->dom->createElement('latitude',$lat));
      $look->appendChild($this->dom->createElement('altitude',$alt));
      $look->appendChild($this->dom->createElement('range',$range));
      $look->appendChild($this->dom->createElement('tilt',$tilt));
      $look->appendChild($this->dom->createElement('heading',$heading));
      $look->appendChild($this->dom->createElement('altitudeMode','relativeToGround'));
      $this->document->appendChild($look);
    }

  }
?>