```/* <![CDATA[ */
function get_sym_list(){return [["Variable","xv",[["geom_type",9]]],["Class","xc",[["Polygon",7]]],["Function","xf",[["area",16],["boundary",12],["centroid",49],["dimension",119],["exteriorRing",105],["interiorRingN",115],["isSimple",124],["length",212],["numInteriorRings",110],["outermostPoint",88],["pointInPolygon",153],["pointOnVertex",201]]]];} /* ]]> */1<?php
2
3/**
4 * Polygon: A polygon is a plane figure that is bounded by a closed path,
5 * composed of a finite sequence of straight line segments
6 */
7class Polygon extends Collection
8{
9  protected \$geom_type = 'Polygon';
10
11  // The boundary of a polygin is it's outer ring
12  public function boundary() {
13    return \$this->exteriorRing();
14  }
15
16  public function area(\$exterior_only = FALSE, \$signed = FALSE) {
17    if (\$this->isEmpty()) return 0;
18
19    if (\$this->geos() && \$exterior_only == FALSE) {
20      return \$this->geos()->area();
21    }
22
23    \$exterior_ring = \$this->components[0];
24    \$pts = \$exterior_ring->getComponents();
25
26    \$c = count(\$pts);
27    if((int)\$c == '0') return NULL;
28    \$a = '0';
29    foreach(\$pts as \$k => \$p){
30      \$j = (\$k + 1) % \$c;
31      \$a = \$a + (\$p->getX() * \$pts[\$j]->getY()) - (\$p->getY() * \$pts[\$j]->getX());
32    }
33
34    if (\$signed) \$area = (\$a / 2);
35    else \$area = abs((\$a / 2));
36
37    if (\$exterior_only == TRUE) {
38      return \$area;
39    }
40    foreach (\$this->components as \$delta => \$component) {
41      if (\$delta != 0) {
42        \$inner_poly = new Polygon(array(\$component));
43        \$area -= \$inner_poly->area();
44      }
45    }
46    return \$area;
47  }
48
49  public function centroid() {
50    if (\$this->isEmpty()) return NULL;
51
52    if (\$this->geos()) {
53      return geoPHP::geosToGeometry(\$this->geos()->centroid());
54    }
55
56    \$exterior_ring = \$this->components[0];
57    \$pts = \$exterior_ring->getComponents();
58
59    \$c = count(\$pts);
60    if((int)\$c == '0') return NULL;
61    \$cn = array('x' => '0', 'y' => '0');
62    \$a = \$this->area(TRUE, TRUE);
63
64    // If this is a polygon with no area. Just return the first point.
65    if (\$a == 0) {
66      return \$this->exteriorRing()->pointN(1);
67    }
68
69    foreach(\$pts as \$k => \$p){
70      \$j = (\$k + 1) % \$c;
71      \$P = (\$p->getX() * \$pts[\$j]->getY()) - (\$p->getY() * \$pts[\$j]->getX());
72      \$cn['x'] = \$cn['x'] + (\$p->getX() + \$pts[\$j]->getX()) * \$P;
73      \$cn['y'] = \$cn['y'] + (\$p->getY() + \$pts[\$j]->getY()) * \$P;
74    }
75
76    \$cn['x'] = \$cn['x'] / ( 6 * \$a);
77    \$cn['y'] = \$cn['y'] / ( 6 * \$a);
78
79    \$centroid = new Point(\$cn['x'], \$cn['y']);
80    return \$centroid;
81  }
82
83	/**
84	 * Find the outermost point from the centroid
85	 *
86	 * @returns Point The outermost point
87	 */
88  public function outermostPoint() {
89		\$centroid = \$this->getCentroid();
90
91		\$max = array('length' => 0, 'point' => null);
92
93		foreach(\$this->getPoints() as \$point) {
94			\$lineString = new LineString(array(\$centroid, \$point));
95
96			if(\$lineString->length() > \$max['length']) {
97				\$max['length'] = \$lineString->length();
98				\$max['point'] = \$point;
99			}
100		}
101
102		return \$max['point'];
103  }
104
105  public function exteriorRing() {
106    if (\$this->isEmpty()) return new LineString();
107    return \$this->components[0];
108  }
109
110  public function numInteriorRings() {
111    if (\$this->isEmpty()) return 0;
112    return \$this->numGeometries()-1;
113  }
114
115  public function interiorRingN(\$n) {
116    return \$this->geometryN(\$n+1);
117  }
118
119  public function dimension() {
120    if (\$this->isEmpty()) return 0;
121    return 2;
122  }
123
124  public function isSimple() {
125    if (\$this->geos()) {
126      return \$this->geos()->isSimple();
127    }
128
129    \$segments = \$this->explode();
130
131    foreach (\$segments as \$i => \$segment) {
132      foreach (\$segments as \$j => \$check_segment) {
133        if (\$i != \$j) {
134          if (\$segment->lineSegmentIntersect(\$check_segment)) {
135            return FALSE;
136          }
137        }
138      }
139    }
140    return TRUE;
141  }
142
143  /**
144   * For a given point, determine whether it's bounded by the given polygon.
146   * @see http://en.wikipedia.org/wiki/Point%5Fin%5Fpolygon
147   *
148   * @param Point \$point
149   * @param boolean \$pointOnBoundary - whether a boundary should be considered "in" or not
150   * @param boolean \$pointOnVertex - whether a vertex should be considered "in" or not
151   * @return boolean
152   */
153  public function pointInPolygon(\$point, \$pointOnBoundary = true, \$pointOnVertex = true) {
154    \$vertices = \$this->getPoints();
155
156    // Check if the point sits exactly on a vertex
157    if (\$this->pointOnVertex(\$point, \$vertices)) {
158      return \$pointOnVertex ? TRUE : FALSE;
159    }
160
161    // Check if the point is inside the polygon or on the boundary
162    \$intersections = 0;
163    \$vertices_count = count(\$vertices);
164
165    for (\$i=1; \$i < \$vertices_count; \$i++) {
166      \$vertex1 = \$vertices[\$i-1];
167      \$vertex2 = \$vertices[\$i];
168      if (\$vertex1->y() == \$vertex2->y()
169      && \$vertex1->y() == \$point->y()
170      && \$point->x() > min(\$vertex1->x(), \$vertex2->x())
171      && \$point->x() < max(\$vertex1->x(), \$vertex2->x())) {
172        // Check if point is on an horizontal polygon boundary
173        return \$pointOnBoundary ? TRUE : FALSE;
174      }
175      if (\$point->y() > min(\$vertex1->y(), \$vertex2->y())
176      && \$point->y() <= max(\$vertex1->y(), \$vertex2->y())
177      && \$point->x() <= max(\$vertex1->x(), \$vertex2->x())
178      && \$vertex1->y() != \$vertex2->y()) {
179        \$xinters =
180          (\$point->y() - \$vertex1->y()) * (\$vertex2->x() - \$vertex1->x())
181          / (\$vertex2->y() - \$vertex1->y())
182          + \$vertex1->x();
183        if (\$xinters == \$point->x()) {
184          // Check if point is on the polygon boundary (other than horizontal)
185          return \$pointOnBoundary ? TRUE : FALSE;
186        }
187        if (\$vertex1->x() == \$vertex2->x() || \$point->x() <= \$xinters) {
188          \$intersections++;
189        }
190      }
191    }
192    // If the number of edges we passed through is even, then it's in the polygon.
193    if (\$intersections % 2 != 0) {
194      return TRUE;
195    }
196    else {
197      return FALSE;
198    }
199  }
200
201  public function pointOnVertex(\$point) {
202    foreach(\$this->getPoints() as \$vertex) {
203      if (\$point->equals(\$vertex)) {
204        return true;
205      }
206    }
207  }
208
209
210  // Not valid for this geometry type
211  // --------------------------------
212  public function length() { return NULL; }
213
214}
215
216```