90 lines
2.9 KiB
JavaScript
90 lines
2.9 KiB
JavaScript
/* Copyright (c) 2006-2012 by OpenLayers Contributors (see authors.txt for
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* full list of contributors). Published under the Clear BSD license.
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* See http://svn.openlayers.org/trunk/openlayers/license.txt for the
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* full text of the license. */
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/**
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* @requires OpenLayers/Geometry/MultiPoint.js
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*/
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/**
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* Class: OpenLayers.Geometry.Curve
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* A Curve is a MultiPoint, whose points are assumed to be connected. To
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* this end, we provide a "getLength()" function, which iterates through
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* the points, summing the distances between them.
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*
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* Inherits:
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* - <OpenLayers.Geometry.MultiPoint>
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*/
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OpenLayers.Geometry.Curve = OpenLayers.Class(OpenLayers.Geometry.MultiPoint, {
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/**
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* Property: componentTypes
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* {Array(String)} An array of class names representing the types of
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* components that the collection can include. A null
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* value means the component types are not restricted.
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*/
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componentTypes: ["OpenLayers.Geometry.Point"],
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/**
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* Constructor: OpenLayers.Geometry.Curve
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*
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* Parameters:
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* point - {Array(<OpenLayers.Geometry.Point>)}
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*/
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/**
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* APIMethod: getLength
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*
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* Returns:
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* {Float} The length of the curve
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*/
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getLength: function() {
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var length = 0.0;
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if ( this.components && (this.components.length > 1)) {
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for(var i=1, len=this.components.length; i<len; i++) {
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length += this.components[i-1].distanceTo(this.components[i]);
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}
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}
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return length;
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},
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/**
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* APIMethod: getGeodesicLength
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* Calculate the approximate length of the geometry were it projected onto
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* the earth.
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*
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* projection - {<OpenLayers.Projection>} The spatial reference system
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* for the geometry coordinates. If not provided, Geographic/WGS84 is
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* assumed.
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*
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* Returns:
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* {Float} The appoximate geodesic length of the geometry in meters.
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*/
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getGeodesicLength: function(projection) {
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var geom = this; // so we can work with a clone if needed
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if(projection) {
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var gg = new OpenLayers.Projection("EPSG:4326");
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if(!gg.equals(projection)) {
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geom = this.clone().transform(projection, gg);
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}
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}
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var length = 0.0;
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if(geom.components && (geom.components.length > 1)) {
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var p1, p2;
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for(var i=1, len=geom.components.length; i<len; i++) {
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p1 = geom.components[i-1];
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p2 = geom.components[i];
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// this returns km and requires lon/lat properties
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length += OpenLayers.Util.distVincenty(
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{lon: p1.x, lat: p1.y}, {lon: p2.x, lat: p2.y}
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);
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}
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}
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// convert to m
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return length * 1000;
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},
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CLASS_NAME: "OpenLayers.Geometry.Curve"
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});
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