radar-wp/vendor/phayes/geophp/lib/geometry/Polygon.class.php

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2015-02-24 16:25:12 +01:00
<?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; }
}