Initial import.

vendor/phayes/geophp/lib/geometry/Polygon.class.php

@@ -0,0 +1,215 @@
+<?php
+
+/**
+ * Polygon: A polygon is a plane figure that is bounded by a closed path, 
+ * composed of a finite sequence of straight line segments
+ */
+class Polygon extends Collection
+{
+  protected $geom_type = 'Polygon';
+
+  // The boundary of a polygin is it's outer ring
+  public function boundary() {
+    return $this->exteriorRing();
+  }
+
+  public function area($exterior_only = FALSE, $signed = FALSE) {
+    if ($this->isEmpty()) return 0;
+    
+    if ($this->geos() && $exterior_only == FALSE) {
+      return $this->geos()->area();
+    }
+    
+    $exterior_ring = $this->components[0];
+    $pts = $exterior_ring->getComponents();
+    
+    $c = count($pts);
+    if((int)$c == '0') return NULL;
+    $a = '0';
+    foreach($pts as $k => $p){
+      $j = ($k + 1) % $c;
+      $a = $a + ($p->getX() * $pts[$j]->getY()) - ($p->getY() * $pts[$j]->getX());
+    }
+    
+    if ($signed) $area = ($a / 2);
+    else $area = abs(($a / 2));
+    
+    if ($exterior_only == TRUE) {
+      return $area;
+    }
+    foreach ($this->components as $delta => $component) {
+      if ($delta != 0) {
+        $inner_poly = new Polygon(array($component));
+        $area -= $inner_poly->area();
+      }
+    }
+    return $area;
+  }
+  
+  public function centroid() {
+    if ($this->isEmpty()) return NULL;
+    
+    if ($this->geos()) {
+      return geoPHP::geosToGeometry($this->geos()->centroid());
+    }
+    
+    $exterior_ring = $this->components[0];
+    $pts = $exterior_ring->getComponents();
+    
+    $c = count($pts);
+    if((int)$c == '0') return NULL;
+    $cn = array('x' => '0', 'y' => '0');
+    $a = $this->area(TRUE, TRUE);
+    
+    // If this is a polygon with no area. Just return the first point.
+    if ($a == 0) {
+      return $this->exteriorRing()->pointN(1);
+    }
+    
+    foreach($pts as $k => $p){
+      $j = ($k + 1) % $c;
+      $P = ($p->getX() * $pts[$j]->getY()) - ($p->getY() * $pts[$j]->getX());
+      $cn['x'] = $cn['x'] + ($p->getX() + $pts[$j]->getX()) * $P;
+      $cn['y'] = $cn['y'] + ($p->getY() + $pts[$j]->getY()) * $P;
+    }
+    
+    $cn['x'] = $cn['x'] / ( 6 * $a);
+    $cn['y'] = $cn['y'] / ( 6 * $a);
+    
+    $centroid = new Point($cn['x'], $cn['y']);
+    return $centroid;
+  }
+
+	/**
+	 * Find the outermost point from the centroid
+	 *
+	 * @returns Point The outermost point
+	 */
+  public function outermostPoint() {
+		$centroid = $this->getCentroid();
+
+		$max = array('length' => 0, 'point' => null);
+
+		foreach($this->getPoints() as $point) {
+			$lineString = new LineString(array($centroid, $point));
+
+			if($lineString->length() > $max['length']) {
+				$max['length'] = $lineString->length();
+				$max['point'] = $point;
+			}
+		}
+
+		return $max['point'];
+  }
+
+  public function exteriorRing() {
+    if ($this->isEmpty()) return new LineString();
+    return $this->components[0];
+  }
+  
+  public function numInteriorRings() {
+    if ($this->isEmpty()) return 0;
+    return $this->numGeometries()-1;
+  }
+  
+  public function interiorRingN($n) {
+    return $this->geometryN($n+1);
+  }
+  
+  public function dimension() {
+    if ($this->isEmpty()) return 0;
+    return 2;
+  }
+
+  public function isSimple() {
+    if ($this->geos()) {
+      return $this->geos()->isSimple();
+    }
+    
+    $segments = $this->explode();
+    
+    foreach ($segments as $i => $segment) {
+      foreach ($segments as $j => $check_segment) {
+        if ($i != $j) {
+          if ($segment->lineSegmentIntersect($check_segment)) {
+            return FALSE;
+          }
+        }
+      }
+    }
+    return TRUE;
+  }
+
+  /**
+   * For a given point, determine whether it's bounded by the given polygon.
+   * Adapted from http://www.assemblysys.com/dataServices/php_pointinpolygon.php
+   * @see http://en.wikipedia.org/wiki/Point%5Fin%5Fpolygon
+   *
+   * @param Point $point 
+   * @param boolean $pointOnBoundary - whether a boundary should be considered "in" or not
+   * @param boolean $pointOnVertex - whether a vertex should be considered "in" or not
+   * @return boolean
+   */
+  public function pointInPolygon($point, $pointOnBoundary = true, $pointOnVertex = true) {
+    $vertices = $this->getPoints();
+
+    // Check if the point sits exactly on a vertex
+    if ($this->pointOnVertex($point, $vertices)) {
+      return $pointOnVertex ? TRUE : FALSE;
+    }
+  
+    // Check if the point is inside the polygon or on the boundary
+    $intersections = 0; 
+    $vertices_count = count($vertices);
+
+    for ($i=1; $i < $vertices_count; $i++) {
+      $vertex1 = $vertices[$i-1]; 
+      $vertex2 = $vertices[$i];
+      if ($vertex1->y() == $vertex2->y() 
+      && $vertex1->y() == $point->y() 
+      && $point->x() > min($vertex1->x(), $vertex2->x()) 
+      && $point->x() < max($vertex1->x(), $vertex2->x())) {
+        // Check if point is on an horizontal polygon boundary
+        return $pointOnBoundary ? TRUE : FALSE;
+      }
+      if ($point->y() > min($vertex1->y(), $vertex2->y())
+      && $point->y() <= max($vertex1->y(), $vertex2->y())
+      && $point->x() <= max($vertex1->x(), $vertex2->x())
+      && $vertex1->y() != $vertex2->y()) {
+        $xinters = 
+          ($point->y() - $vertex1->y()) * ($vertex2->x() - $vertex1->x())
+          / ($vertex2->y() - $vertex1->y()) 
+          + $vertex1->x();
+        if ($xinters == $point->x()) {
+          // Check if point is on the polygon boundary (other than horizontal)
+          return $pointOnBoundary ? TRUE : FALSE;
+        }
+        if ($vertex1->x() == $vertex2->x() || $point->x() <= $xinters) {
+          $intersections++;
+        }
+      } 
+    } 
+    // If the number of edges we passed through is even, then it's in the polygon.
+    if ($intersections % 2 != 0) {
+      return TRUE;
+    }
+    else {
+      return FALSE;
+    }
+  }
+  
+  public function pointOnVertex($point) {
+    foreach($this->getPoints() as $vertex) {
+      if ($point->equals($vertex)) {
+        return true;
+      }
+    }
+  }
+
+
+  // Not valid for this geometry type
+  // --------------------------------
+  public function length() { return NULL; }
+  
+}
+