From 39d06b5ddc0a91e9c3dc7a2233ac9d5f36222dde Mon Sep 17 00:00:00 2001
From: Patrick Hayes <patrick.d.hayes@gmail.com>
Date: Tue, 12 Apr 2011 18:55:46 -0700
Subject: [PATCH] Adding GPX adapter

---
 geoPHP.inc                 |  13 ++-
 lib/adapters/GPX.class.php | 176 +++++++++++++++++++++++++++++++++++++
 2 files changed, 186 insertions(+), 3 deletions(-)
 create mode 100644 lib/adapters/GPX.class.php

diff --git a/geoPHP.inc b/geoPHP.inc
index 3efcefac..99a4cd46 100644
--- a/geoPHP.inc
+++ b/geoPHP.inc
@@ -7,15 +7,21 @@
  * file that was distributed with this source code.
  */
 
+// Geometry Loader (Depreciated)
 include_once("lib/GeometryLoader.class.php");
-include_once("lib/adapters/GeoAdapter.class.php");
+
+// Adapters
+include_once("lib/adapters/GeoAdapter.class.php"); // Abtract class
 include_once("lib/adapters/GeoJSON.class.php");
 include_once("lib/adapters/WKT.class.php");
 include_once("lib/adapters/KML.class.php");
+include_once("lib/adapters/GPX.class.php");
 include_once("lib/adapters/GoogleGeocode.class.php");
-include_once("lib/geometry/Geometry.class.php");
+
+// Geometries
+include_once("lib/geometry/Geometry.class.php"); // Abtract class
 include_once("lib/geometry/Point.class.php");
-include_once("lib/geometry/Collection.class.php");
+include_once("lib/geometry/Collection.class.php"); // Abtract class
 include_once("lib/geometry/LineString.class.php");
 include_once("lib/geometry/MultiPoint.class.php");
 include_once("lib/geometry/LinearRing.class.php");
@@ -61,6 +67,7 @@ class geoPHP {
       'wkt' => 'WKT',
       'json' => 'GeoJSON',
       'kml' => 'KML',
+      'gpx' => 'GPX',
       'google_geocode' => 'GoogleGeocode',
     );
   }
diff --git a/lib/adapters/GPX.class.php b/lib/adapters/GPX.class.php
new file mode 100644
index 00000000..4d66dc2d
--- /dev/null
+++ b/lib/adapters/GPX.class.php
@@ -0,0 +1,176 @@
+<?php
+/*
+ * Copyright (c) Patrick Hayes
+ *
+ * This code is open-source and licenced under the Modified BSD License.
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+/**
+ * PHP Geometry/GPX encoder/decoder
+ */
+class GPX extends GeoAdapter
+{
+
+  /**
+   * Read KML string into geometry objects
+   *
+   * @param string $kml A KML string
+   *
+   * @return Geometry|GeometryCollection
+   */
+  public function read($gpx)
+  {
+    return $this->geomFromText($gpx);
+  }
+
+  /**
+   * Serialize geometries into a KML string.
+   *
+   * @param Geometry $geometry
+   *
+   * @return string The KML string representation of the input geometries
+   */
+  public function write(Geometry $geometry)
+  {
+    return $this->geometryToGPX($geometry);
+  }
+  
+  public function geomFromText($text) {
+        // Change to lower-case and strip all CDATA
+        $text = strtolower($text);
+        $text = preg_replace('/<!\[cdata\[(.*?)\]\]>/s','',$text);
+        
+        // Load into DOMDOcument
+        $xmlobj = new DOMDocument();
+        $xmlobj->loadXML($text);
+        if ($xmlobj === false) {
+          throw new Exception("Invalid GPX: ". $text);
+        }
+        
+        $this->xmlobj = $xmlobj;
+        try {
+          $geom = $this->geomFromXML();
+        } catch(InvalidText $e) {
+            throw new Exception("Cannot Read Geometry From GPX: ". $text);
+        } catch(Exception $e) {
+            throw $e;
+        }
+
+        return $geom;
+    }
+    
+    protected function geomFromXML() {
+    	$geometries = array();
+      $geometries = array_merge($geometries, $this->parseWaypoints());
+      $geometries = array_merge($geometries, $this->parseTracks());
+      $geometries = array_merge($geometries, $this->parseRoutes());
+      
+      if (empty($geometries)) {
+      	throw new Exception("Invalid / Empty GPX");
+      }
+      
+      return geoPHP::geometryReduce($geometries); 
+    }
+    
+    protected function childElements($xml, $nodename = '') {
+    	$children = array();
+      foreach ($xml->childNodes as $child) {
+        if ($child->nodeName == $nodename) {
+        	$children[] = $child;
+      	}
+      }
+      return $children;
+    }
+    
+    protected function parseWaypoints() {
+    	$points = array();
+      $wpt_elements = $this->xmlobj->getElementsByTagName('wpt');
+      foreach ($wpt_elements as $wpt) {
+        $lat = $wpt->attributes->getNamedItem("lat")->nodeValue;
+        $lon = $wpt->attributes->getNamedItem("lon")->nodeValue;
+        $points[] = new Point($lon, $lat);
+      }
+      return $points;
+    }
+    
+    protected function parseTracks() {
+    	$lines = array();
+      $trk_elements = $this->xmlobj->getElementsByTagName('trk');
+      foreach ($trk_elements as $trk) {
+      	$components = array();
+      	foreach ($this->childElements($trk, 'trkseg') as $trkseg) {
+	      	foreach ($this->childElements($trkseg, 'trkpt') as $trkpt) {
+		        $lat = $trkpt->attributes->getNamedItem("lat")->nodeValue;
+		        $lon = $trkpt->attributes->getNamedItem("lon")->nodeValue;
+		        $components[] = new Point($lon, $lat);
+	      	}
+      	}
+      	$lines[] = new LineString($components);
+      }
+      return $lines;
+    }
+    
+    protected function parseRoutes() {
+    	$lines = array();
+      $rte_elements = $this->xmlobj->getElementsByTagName('rte');
+      foreach ($rte_elements as $rte) {
+      	$components = array();
+      	foreach ($this->childElements($rte, 'rtept') as $rtept) {
+	        $lat = $rtept->attributes->getNamedItem("lat")->nodeValue;
+	        $lon = $rtept->attributes->getNamedItem("lon")->nodeValue;
+	        $components[] = new Point($lon, $lat);
+      	}
+      	$lines[] = new LineString($components);
+      }
+      return $lines;
+    }
+    
+    private function geometryToGPX($geom) {
+      $type = strtolower($geom->getGeomType());
+      switch ($type) {
+          case 'point':
+              return $this->pointToGPX($geom);
+              break;
+          case 'linestring':
+          case 'linearring':
+              return $this->linestringToGPX($geom);
+              break;
+          case 'polygon':
+          case 'multipoint':
+          case 'multilinestring':
+          case 'multipolygon':
+          case 'geometrycollection':
+              return $this->collectionToGPX($geom);
+              break;
+      }
+    }
+
+    private function pointToGPX($geom) {
+      return '<wpt lat="'.$geom->getY().'" lon="'.$geom->getX().'"></wpt>';
+    }
+
+    private function linestringToGPX($geom) {
+    	$gpx = '<trk><trkseg>';
+    	
+      foreach ($geom->getComponents() as $comp) {
+      	$gpx .= '<trkpt lat="'.$comp->getY().'" lon="'.$comp->getX().'"></trkpt>';
+      }
+      
+      $gpx .= '</trkseg></trk>';
+
+      return $gpx;
+    }
+    
+    public function collectionToGPX($geom) {
+    	$gpx = '';
+      $components = $geom->getComponents();
+      foreach ($geom->getComponents() as $comp) {
+        $gpx .= $this->geometryToGPX($comp);
+      }
+
+      return $gpx;
+    }
+
+}