openlayers/lib/OpenLayers/Layer/PointTrack.js

   1 /* Copyright (c) 2006-2007 MetaCarta, Inc., published under the Clear BSD
   2  * license.  See http://svn.openlayers.org/trunk/openlayers/license.txt for the
   3  * full text of the license. */
   4
   5 /**
   6  * @requires OpenLayers/Layer/Vector.js
   7  * @requires OpenLayers/Console.js
   8  */
   9
  10 /**
  11  * Class: OpenLayers.Layer.PointTrack
  12  * Vector layer to display ordered point features as a line, creating one
  13  * LineString feature for each pair of two points.
  14  *
  15  * Inherits from:
  16  *  - <OpenLayers.Layer.Vector>
  17  */
  18 OpenLayers.Layer.PointTrack = OpenLayers.Class(OpenLayers.Layer.Vector, {
  19
  20     /**
  21      * APIProperty:
  22      * dataFrom  - {<OpenLayers.Layer.PointTrack.dataFrom>} optional. If the
  23      *             lines should get the data/attributes from one of the two
  24      *             points, creating it, which one should it be?
  25      */
  26     dataFrom: null,
  27
  28     /**
  29      * Constructor: OpenLayers.PointTrack
  30      * Constructor for a new OpenLayers.PointTrack instance.
  31      *
  32      * Parameters:
  33      * name     - {String} name of the layer
  34      * options  - {Object} Optional object with properties to tag onto the
  35      *            instance.
  36      */
  37     initialize: function(name, options) {
  38         OpenLayers.Layer.Vector.prototype.initialize.apply(this, arguments);
  39     },
  40
  41     /**
  42      * APIMethod: addNodes
  43      * Adds point features that will be used to create lines from, using point
  44      * pairs. The first point of a pair will be the source node, the second
  45      * will be the target node.
  46      *
  47      * Parameters:
  48      * pointFeatures - {Array(<OpenLayers.Feature>)}
  49      *
  50      */
  51     addNodes: function(pointFeatures) {
  52         if (pointFeatures.length < 2) {
  53             OpenLayers.Console.error(
  54                     "At least two point features have to be added to create" +
  55                     "a line from");
  56             return;
  57         }
  58
  59         var lines = new Array(pointFeatures.length-1);
  60
  61         var pointFeature, startPoint, endPoint;
  62         for(var i=0, len=pointFeatures.length; i<len; i++) {
  63             pointFeature = pointFeatures[i];
  64             endPoint = pointFeature.geometry;
  65
  66             if (!endPoint) {
  67               var lonlat = pointFeature.lonlat;
  68               endPoint = new OpenLayers.Geometry.Point(lonlat.lon, lonlat.lat);
  69             } else if(endPoint.CLASS_NAME != "OpenLayers.Geometry.Point") {
  70                 OpenLayers.Console.error(
  71                         "Only features with point geometries are supported.");
  72                 return;
  73             }
  74
  75             if(i > 0) {
  76                 var attributes = (this.dataFrom != null) ?
  77                         (pointFeatures[i+this.dataFrom].data ||
  78                                 pointFeatures[i+this.dataFrom].attributes) :
  79                         null;
  80                 var line = new OpenLayers.Geometry.LineString([startPoint,
  81                         endPoint]);
  82
  83                 lines[i-1] = new OpenLayers.Feature.Vector(line, attributes);
  84             }
  85
  86             startPoint = endPoint;
  87         }
  88
  89         this.addFeatures(lines);
  90     },
  91
  92     CLASS_NAME: "OpenLayers.Layer.PointTrack"
  93 });
  94
  95 /**
  96  * Constant: OpenLayers.Layer.PointTrack.dataFrom
  97  * {Object} with the following keys
  98  * - SOURCE_NODE: take data/attributes from the source node of the line
  99  * - TARGET_NODE: take data/attributes from the target node of the line
 100  */
 101 OpenLayers.Layer.PointTrack.dataFrom = {'SOURCE_NODE': -1, 'TARGET_NODE': 0};
 102