| /* Copyright (c) 2006-2010 by OpenLayers Contributors (see authors.txt for | |
| * full list of contributors). Published under the Clear BSD license. | |
| * See http://svn.openlayers.org/trunk/openlayers/license.txt for the | |
| * full text of the license. */ | |
| /** | |
| * @requires OpenLayers/Geometry/Collection.js | |
| * @requires OpenLayers/Geometry/LinearRing.js | |
| */ | |
| /** | |
| * Class: OpenLayers.Geometry.Polygon | |
| * Polygon is a collection of Geometry.LinearRings. | |
| * | |
| * Inherits from: | |
| * - <OpenLayers.Geometry.Collection> | |
| * - <OpenLayers.Geometry> | |
| */ | |
| OpenLayers.Geometry.Polygon = OpenLayers.Class( | |
| OpenLayers.Geometry.Collection, { | |
| /** | |
| * Property: componentTypes | |
| * {Array(String)} An array of class names representing the types of | |
| * components that the collection can include. A null value means the | |
| * component types are not restricted. | |
| */ | |
| componentTypes: ["OpenLayers.Geometry.LinearRing"], | |
| /** | |
| * Constructor: OpenLayers.Geometry.Polygon | |
| * Constructor for a Polygon geometry. | |
| * The first ring (this.component[0])is the outer bounds of the polygon and | |
| * all subsequent rings (this.component[1-n]) are internal holes. | |
| * | |
| * | |
| * Parameters: | |
| * components - {Array(<OpenLayers.Geometry.LinearRing>)} | |
| */ | |
| initialize: function(components) { | |
| OpenLayers.Geometry.Collection.prototype.initialize.apply(this, | |
| arguments); | |
| }, | |
| /** | |
| * APIMethod: getArea | |
| * Calculated by subtracting the areas of the internal holes from the | |
| * area of the outer hole. | |
| * | |
| * Returns: | |
| * {float} The area of the geometry | |
| */ | |
| getArea: function() { | |
| var area = 0.0; | |
| if ( this.components && (this.components.length > 0)) { | |
| area += Math.abs(this.components[0].getArea()); | |
| for (var i=1, len=this.components.length; i<len; i++) { | |
| area -= Math.abs(this.components[i].getArea()); | |
| } | |
| } | |
| return area; | |
| }, | |
| /** | |
| * APIMethod: getGeodesicArea | |
| * Calculate the approximate area of the polygon were it projected onto | |
| * the earth. | |
| * | |
| * Parameters: | |
| * projection - {<OpenLayers.Projection>} The spatial reference system | |
| * for the geometry coordinates. If not provided, Geographic/WGS84 is | |
| * assumed. | |
| * | |
| * Reference: | |
| * Robert. G. Chamberlain and William H. Duquette, "Some Algorithms for | |
| * Polygons on a Sphere", JPL Publication 07-03, Jet Propulsion | |
| * Laboratory, Pasadena, CA, June 2007 http://trs-new.jpl.nasa.gov/dspace/handle/2014/40409 | |
| * | |
| * Returns: | |
| * {float} The approximate geodesic area of the polygon in square meters. | |
| */ | |
| getGeodesicArea: function(projection) { | |
| var area = 0.0; | |
| if(this.components && (this.components.length > 0)) { | |
| area += Math.abs(this.components[0].getGeodesicArea(projection)); | |
| for(var i=1, len=this.components.length; i<len; i++) { | |
| area -= Math.abs(this.components[i].getGeodesicArea(projection)); | |
| } | |
| } | |
| return area; | |
| }, | |
| /** | |
| * Method: containsPoint | |
| * Test if a point is inside a polygon. Points on a polygon edge are | |
| * considered inside. | |
| * | |
| * Parameters: | |
| * point - {<OpenLayers.Geometry.Point>} | |
| * | |
| * Returns: | |
| * {Boolean | Number} The point is inside the polygon. Returns 1 if the | |
| * point is on an edge. Returns boolean otherwise. | |
| */ | |
| containsPoint: function(point) { | |
| var numRings = this.components.length; | |
| var contained = false; | |
| if(numRings > 0) { | |
| // check exterior ring - 1 means on edge, boolean otherwise | |
| contained = this.components[0].containsPoint(point); | |
| if(contained !== 1) { | |
| if(contained && numRings > 1) { | |
| // check interior rings | |
| var hole; | |
| for(var i=1; i<numRings; ++i) { | |
| hole = this.components[i].containsPoint(point); | |
| if(hole) { | |
| if(hole === 1) { | |
| // on edge | |
| contained = 1; | |
| } else { | |
| // in hole | |
| contained = false; | |
| } | |
| break; | |
| } | |
| } | |
| } | |
| } | |
| } | |
| return contained; | |
| }, | |
| /** | |
| * APIMethod: intersects | |
| * Determine if the input geometry intersects this one. | |
| * | |
| * Parameters: | |
| * geometry - {<OpenLayers.Geometry>} Any type of geometry. | |
| * | |
| * Returns: | |
| * {Boolean} The input geometry intersects this one. | |
| */ | |
| intersects: function(geometry) { | |
| var intersect = false; | |
| var i, len; | |
| if(geometry.CLASS_NAME == "OpenLayers.Geometry.Point") { | |
| intersect = this.containsPoint(geometry); | |
| } else if(geometry.CLASS_NAME == "OpenLayers.Geometry.LineString" || | |
| geometry.CLASS_NAME == "OpenLayers.Geometry.LinearRing") { | |
| // check if rings/linestrings intersect | |
| for(i=0, len=this.components.length; i<len; ++i) { | |
| intersect = geometry.intersects(this.components[i]); | |
| if(intersect) { | |
| break; | |
| } | |
| } | |
| if(!intersect) { | |
| // check if this poly contains points of the ring/linestring | |
| for(i=0, len=geometry.components.length; i<len; ++i) { | |
| intersect = this.containsPoint(geometry.components[i]); | |
| if(intersect) { | |
| break; | |
| } | |
| } | |
| } | |
| } else { | |
| for(i=0, len=geometry.components.length; i<len; ++ i) { | |
| intersect = this.intersects(geometry.components[i]); | |
| if(intersect) { | |
| break; | |
| } | |
| } | |
| } | |
| // check case where this poly is wholly contained by another | |
| if(!intersect && geometry.CLASS_NAME == "OpenLayers.Geometry.Polygon") { | |
| // exterior ring points will be contained in the other geometry | |
| var ring = this.components[0]; | |
| for(i=0, len=ring.components.length; i<len; ++i) { | |
| intersect = geometry.containsPoint(ring.components[i]); | |
| if(intersect) { | |
| break; | |
| } | |
| } | |
| } | |
| return intersect; | |
| }, | |
| /** | |
| * APIMethod: distanceTo | |
| * Calculate the closest distance between two geometries (on the x-y plane). | |
| * | |
| * Parameters: | |
| * geometry - {<OpenLayers.Geometry>} The target geometry. | |
| * options - {Object} Optional properties for configuring the distance | |
| * calculation. | |
| * | |
| * Valid options: | |
| * details - {Boolean} Return details from the distance calculation. | |
| * Default is false. | |
| * edge - {Boolean} Calculate the distance from this geometry to the | |
| * nearest edge of the target geometry. Default is true. If true, | |
| * calling distanceTo from a geometry that is wholly contained within | |
| * the target will result in a non-zero distance. If false, whenever | |
| * geometries intersect, calling distanceTo will return 0. If false, | |
| * details cannot be returned. | |
| * | |
| * Returns: | |
| * {Number | Object} The distance between this geometry and the target. | |
| * If details is true, the return will be an object with distance, | |
| * x0, y0, x1, and y1 properties. The x0 and y0 properties represent | |
| * the coordinates of the closest point on this geometry. The x1 and y1 | |
| * properties represent the coordinates of the closest point on the | |
| * target geometry. | |
| */ | |
| distanceTo: function(geometry, options) { | |
| var edge = !(options && options.edge === false); | |
| var result; | |
| // this is the case where we might not be looking for distance to edge | |
| if(!edge && this.intersects(geometry)) { | |
| result = 0; | |
| } else { | |
| result = OpenLayers.Geometry.Collection.prototype.distanceTo.apply( | |
| this, [geometry, options] | |
| ); | |
| } | |
| return result; | |
| }, | |
| CLASS_NAME: "OpenLayers.Geometry.Polygon" | |
| }); | |
| /** | |
| * APIMethod: createRegularPolygon | |
| * Create a regular polygon around a radius. Useful for creating circles | |
| * and the like. | |
| * | |
| * Parameters: | |
| * origin - {<OpenLayers.Geometry.Point>} center of polygon. | |
| * radius - {Float} distance to vertex, in map units. | |
| * sides - {Integer} Number of sides. 20 approximates a circle. | |
| * rotation - {Float} original angle of rotation, in degrees. | |
| */ | |
| OpenLayers.Geometry.Polygon.createRegularPolygon = function(origin, radius, sides, rotation) { | |
| var angle = Math.PI * ((1/sides) - (1/2)); | |
| if(rotation) { | |
| angle += (rotation / 180) * Math.PI; | |
| } | |
| var rotatedAngle, x, y; | |
| var points = []; | |
| for(var i=0; i<sides; ++i) { | |
| rotatedAngle = angle + (i * 2 * Math.PI / sides); | |
| x = origin.x + (radius * Math.cos(rotatedAngle)); | |
| y = origin.y + (radius * Math.sin(rotatedAngle)); | |
| points.push(new OpenLayers.Geometry.Point(x, y)); | |
| } | |
| var ring = new OpenLayers.Geometry.LinearRing(points); | |
| return new OpenLayers.Geometry.Polygon([ring]); | |
| }; | |