map.js

用来在地图上做操作GIS,在地图上做标记

        
        this.maxExtent = new OpenLayers.Bounds(-180, -90, 180, 90);

        this.theme = OpenLayers._getScriptLocation() + 
                             'theme/default/style.css'; 

        // now add the options declared by the user
        //  (these will override defaults)
        OpenLayers.Util.extend(this, options);
    },

    /**
     * APIMethod: getTileSize
     * Get the tile size for the map
     *
     * Returns:
     * {<OpenLayers.Size>}
     */
     getTileSize: function() {
         return this.tileSize;
     },

  /********************************************************/
  /*                                                      */
  /*                  Layer Functions                     */
  /*                                                      */
  /*     The following functions deal with adding and     */
  /*        removing Layers to and from the Map           */
  /*                                                      */
  /********************************************************/         

    /**
     * APIMethod: getLayer
     * Get a layer based on its id
     *
     * Parameter:
     * id - {String} A layer id
     *
     * Returns:
     * {<OpenLayers.Layer>} The Layer with the corresponding id from the map's 
     *                      layer collection, or null if not found.
     */
    getLayer: function(id) {
        var foundLayer = null;
        for (var i = 0; i < this.layers.length; i++) {
            var layer = this.layers[i];
            if (layer.id == id) {
                foundLayer = layer;
            }
        }
        return foundLayer;
    },

    /**
    * Method: setLayerZIndex
    * 
    * Parameters:
    * layer - {<OpenLayers.Layer>} 
    * zIdx - {int} 
    */    
    setLayerZIndex: function (layer, zIdx) {
        layer.setZIndex(
            this.Z_INDEX_BASE[layer.isBaseLayer ? 'BaseLayer' : 'Overlay']
            + zIdx * 5 );
    },

    /**
    * APIMethod: addLayer
    *
    * Parameters:
    * layer - {<OpenLayers.Layer>} 
    */    
    addLayer: function (layer) {
        for(var i=0; i < this.layers.length; i++) {
            if (this.layers[i] == layer) {
                var msg = "You tried to add the layer: " + layer.name + 
                          " to the map, but it has already been added";
                OpenLayers.Console.warn(msg);
                return false;
            }
        }    
        
        layer.div.style.overflow = "";
        this.setLayerZIndex(layer, this.layers.length);

        if (layer.isFixed) {
            this.viewPortDiv.appendChild(layer.div);
        } else {
            this.layerContainerDiv.appendChild(layer.div);
        }
        this.layers.push(layer);
        layer.setMap(this);

        if (layer.isBaseLayer)  {
            if (this.baseLayer == null) {
                // set the first baselaye we add as the baselayer
                this.setBaseLayer(layer);
            } else {
                layer.setVisibility(false);
            }
        } else {
            layer.redraw();
        }

        this.events.triggerEvent("addlayer");
    },

    /**
    * APIMethod: addLayers 
    *
    * Parameters:
    * layers - Array({<OpenLayers.Layer>}) 
    */    
    addLayers: function (layers) {
        for (var i = 0; i <  layers.length; i++) {
            this.addLayer(layers[i]);
        }
    },

    /** 
     * APIMethod: removeLayer
     * Removes a layer from the map by removing its visual element (the 
     *   layer.div property), then removing it from the map's internal list 
     *   of layers, setting the layer's map property to null. 
     * 
     *   a "removelayer" event is triggered.
     * 
     *   very worthy of mention is that simply removing a layer from a map
     *   will not cause the removal of any popups which may have been created
     *   by the layer. this is due to the fact that it was decided at some
     *   point that popups would not belong to layers. thus there is no way 
     *   for us to know here to which layer the popup belongs.
     *    
     *     A simple solution to this is simply to call destroy() on the layer.
     *     the default OpenLayers.Layer class's destroy() function
     *     automatically takes care to remove itself from whatever map it has
     *     been attached to. 
     * 
     *     The correct solution is for the layer itself to register an 
     *     event-handler on "removelayer" and when it is called, if it 
     *     recognizes itself as the layer being removed, then it cycles through
     *     its own personal list of popups, removing them from the map.
     * 
     * Parameters:
     * layer - {<OpenLayers.Layer>} 
     * setNewBaseLayer - {Boolean} Default is true
     */
    removeLayer: function(layer, setNewBaseLayer) {
        if (setNewBaseLayer == null) {
            setNewBaseLayer = true;
        }

        if (layer.isFixed) {
            this.viewPortDiv.removeChild(layer.div);
        } else {
            this.layerContainerDiv.removeChild(layer.div);
        }
        OpenLayers.Util.removeItem(this.layers, layer);
        layer.removeMap(this);
        layer.map = null;

        // if we removed the base layer, need to set a new one
        if (setNewBaseLayer && (this.baseLayer == layer)) {
            this.baseLayer = null;
            for(i=0; i < this.layers.length; i++) {
                var iLayer = this.layers[i];
                if (iLayer.isBaseLayer) {
                    this.setBaseLayer(iLayer);
                    break;
                }
            }
        }
        this.events.triggerEvent("removelayer");
    },

    /**
     * APIMethod: getNumLayers
     * 
     * Returns:
     * {Int} The number of layers attached to the map.
     */
    getNumLayers: function () {
        return this.layers.length;
    },

    /** 
     * APIMethod: getLayerIndex
     *
     * Parameters:
     * layer - {<OpenLayers.Layer>}
     *
     * Returns:
     * {Integer} The current (zero-based) index of the given layer in the map's
     *           layer stack. Returns -1 if the layer isn't on the map.
     */
    getLayerIndex: function (layer) {
        return OpenLayers.Util.indexOf(this.layers, layer);
    },
    
    /** 
     * APIMethod: setLayerIndex
     * Move the given layer to the specified (zero-based) index in the layer
     *     list, changing its z-index in the map display. Use
     *     map.getLayerIndex() to find out the current index of a layer. Note
     *     that this cannot (or at least should not) be effectively used to
     *     raise base layers above overlays.
     *
     * Parameters:
     * layer - {<OpenLayers.Layer>} 
     * idx - {int} 
     */
    setLayerIndex: function (layer, idx) {
        var base = this.getLayerIndex(layer);
        if (idx < 0) {
            idx = 0;
        } else if (idx > this.layers.length) {
            idx = this.layers.length;
        }
        if (base != idx) {
            this.layers.splice(base, 1);
            this.layers.splice(idx, 0, layer);
            for (var i = 0; i < this.layers.length; i++) {
                this.setLayerZIndex(this.layers[i], i);
            }
            this.events.triggerEvent("changelayer");
        }
    },

    /** 
     * APIMethod: raiseLayer
     * Change the index of the given layer by delta. If delta is positive, 
     *     the layer is moved up the map's layer stack; if delta is negative,
     *     the layer is moved down.  Again, note that this cannot (or at least
     *     should not) be effectively used to raise base layers above overlays.
     *
     * Paremeters:
     * layer - {<OpenLayers.Layer>} 
     * idx - {int} 
     */
    raiseLayer: function (layer, delta) {
        var idx = this.getLayerIndex(layer) + delta;
        this.setLayerIndex(layer, idx);
    },
    
    /** 
     * APIMethod: setBaseLayer
     * Allows user to specify one of the currently-loaded layers as the Map's
     *     new base layer.
     * 
     * Parameters:
     * newBaseLayer - {<OpenLayers.Layer>}
     */
    setBaseLayer: function(newBaseLayer) {
        var oldExtent = null;
        if(this.baseLayer) {
            oldExtent = this.baseLayer.getExtent();
        }

        if (newBaseLayer != this.baseLayer) {
          
            // is newBaseLayer an already loaded layer?m
            if (OpenLayers.Util.indexOf(this.layers, newBaseLayer) != -1) {

                // make the old base layer invisible 
                if (this.baseLayer != null) {
                    this.baseLayer.setVisibility(false);
                }

                // set new baselayer and make it visible
                this.baseLayer = newBaseLayer;
                
                // Increment viewRequestID since the baseLayer is 
                // changing. This is used by tiles to check if they should 
                // draw themselves.
                this.viewRequestID++;
                this.baseLayer.visibility = true;

                //redraw all layers
                var center = this.getCenter();
                if (center != null) {
                    if (oldExtent == null) {
                        // simply set center but force zoom change
                        this.setCenter(center, this.getZoom(), false, true);
                    } else {
                        // zoom to oldExtent *and* force zoom change
                        this.setCenter(oldExtent.getCenterLonLat(), 
                                       this.getZoomForExtent(oldExtent, true),
                                       false, true);
                    }
                }

                this.events.triggerEvent("changebaselayer");
            }        
        }
    },


  /********************************************************/
  /*                                                      */
  /*                 Control Functions                    */
  /*                                                      */
  /*     The following functions deal with adding and     */
  /*        removing Controls to and from the Map         */
  /*                                                      */
  /********************************************************/         

    /**
     * APIMethod: addControl
     * 
     * Parameters:
     * control - {<OpenLayers.Control>}
     * px - {<OpenLayers.Pixel>}
     */    
    addControl: function (control, px) {
        this.controls.push(control);
        this.addControlToMap(control, px);
    },

    /**
     * Method: addControlToMap
     * 
     * Parameters:
     * 
     * control - {<OpenLayers.Control>}
     * px - {<OpenLayers.Pixel>}
     */    
    addControlToMap: function (control, px) {
        // If a control doesn't have a div at this point, it belongs in the
        // viewport.
        control.outsideViewport = (control.div != null);
        control.setMap(this);
        var div = control.draw(px);
        if (div) {
            if(!control.outsideViewport) {
                div.style.zIndex = this.Z_INDEX_BASE['Control'] +
                                    this.controls.length;
                this.viewPortDiv.appendChild( div );
            }
        }
    },
    
    /**
     * APIMethod: getControl
     * 
     * Parameters:
     * id - {String} ID of the control to return.
     * 
     * Returns:
     * {<OpenLayers.Control>} The control from the map's list of controls 
     *                        which has a matching 'id'. If none found, 
     *                        returns null.
     */    
    getControl: function (id) {
        var returnControl = null;
        for(var i=0; i < this.controls.length; i++) {
            var control = this.controls[i];
            if (control.id == id) {
                returnControl = control;
                break;
            }
        }
        return returnControl;
    },
    
    /** 
     * APIMethod: removeControl
     * Remove a control from the map. Removes the control both from the map 
     *     object's internal array of controls, as well as from the map's 
     *     viewPort (assuming the control was not added outsideViewport)
     * 
     * Parameters:
     * control - {<OpenLayers.Control>} The control to remove.
     */    
    removeControl: function (control) {
        //make sure control is non-null and actually part of our map
        if ( (control) && (control == this.getControl(control.id)) ) {
            if (!control.outsideViewport) {
                this.viewPortDiv.removeChild(control.div)
            }
            OpenLayers.Util.removeItem(this.controls, control);
        }
    },

  /********************************************************/
  /*                                                      */
  /*                  Popup Functions                     */
  /*                                                      */
  /*     The following functions deal with adding and     */
  /*        removing Popups to and from the Map           */
  /*                                                      */
  /********************************************************/         

    /** 
     * APIMethod: addPopup
     * 
     * Parameters:
     * popup - {<OpenLayers.Popup>}
     * exclusive - {Boolean} If true, closes all other popups first
     */
    addPopup: function(popup, exclusive) {

        if (exclusive) {
            //remove all other popups from screen
            for(var i=0; i < this.popups.length; i++) {
                this.removePopup(this.popups[i]);
            }
        }

        popup.map = this;
        this.popups.push(popup);
        var popupDiv = popup.draw();
        if (popupDiv) {
            popupDiv.style.zIndex = this.Z_INDEX_BASE['Popup'] +
                                    this.popups.length;
            this.layerContainerDiv.appendChild(popupDiv);
        }
    },
    
    /** 
    * APIMethod: removePopup
    * 
    * Parameters:
    * popup - {<OpenLayers.Popup>}