/* 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/MultiPoint.js
*/
/**
* Class: OpenLayers.Geometry.Curve
* A Curve is a MultiPoint, whose points are assumed to be connected. To
* this end, we provide a "getLength()" function, which iterates through
* the points, summing the distances between them.
*
* Inherits:
* - <OpenLayers.Geometry.MultiPoint>
*/
OpenLayers.Geometry.Curve = OpenLayers.Class(OpenLayers.Geometry.MultiPoint, {
/**
* 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.Point"],
/**
* Constructor: OpenLayers.Geometry.Curve
*
* Parameters:
* point - {Array(<OpenLayers.Geometry.Point>)}
*/
initialize: function(points) {
OpenLayers.Geometry.MultiPoint.prototype.initialize.apply(this,
arguments);
},
/**
* APIMethod: getLength
*
* Returns:
* {Float} The length of the curve
*/
getLength: function() {
var length = 0.0;
if ( this.components && (this.components.length > 1)) {
for(var i=1, len=this.components.length; i<len; i++) {
length += this.components[i-1].distanceTo(this.components[i]);
}
}
return length;
},
/**
* APIMethod: getGeodesicLength
* Calculate the approximate length of the geometry were it projected onto
* the earth.
*
* projection - {<OpenLayers.Projection>} The spatial reference system
* for the geometry coordinates. If not provided, Geographic/WGS84 is
* assumed.
*
* Returns:
* {Float} The appoximate geodesic length of the geometry in meters.
*/
getGeodesicLength: function(projection) {
var geom = this; // so we can work with a clone if needed
if(projection) {
var gg = new OpenLayers.Projection("EPSG:4326");
if(!gg.equals(projection)) {
geom = this.clone().transform(projection, gg);
}
}
var length = 0.0;
if(geom.components && (geom.components.length > 1)) {
var p1, p2;
for(var i=1, len=geom.components.length; i<len; i++) {
p1 = geom.components[i-1];
p2 = geom.components[i];
// this returns km and requires lon/lat properties
length += OpenLayers.Util.distVincenty(
{lon: p1.x, lat: p1.y}, {lon: p2.x, lat: p2.y}
);
}
}
// convert to m
return length * 1000;
},
CLASS_NAME: "OpenLayers.Geometry.Curve"
});
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