map.js

用来在地图上做操作GIS,在地图上做标记

    */
    removePopup: function(popup) {
        OpenLayers.Util.removeItem(this.popups, popup);
        if (popup.div) {
            try { this.layerContainerDiv.removeChild(popup.div); }
            catch (e) { } // Popups sometimes apparently get disconnected
                      // from the layerContainerDiv, and cause complaints.
        }
        popup.map = null;
    },

  /********************************************************/
  /*                                                      */
  /*              Container Div Functions                 */
  /*                                                      */
  /*   The following functions deal with the access to    */
  /*    and maintenance of the size of the container div  */
  /*                                                      */
  /********************************************************/     

    /**
     * APIMethod: getSize
     * 
     * Returns:
     * {<OpenLayers.Size>} An <OpenLayers.Size> object that represents the 
     *                     size, in pixels, of the div into which OpenLayers 
     *                     has been loaded. 
     *                     Note - A clone() of this locally cached variable is
     *                     returned, so as not to allow users to modify it.
     */
    getSize: function () {
        var size = null;
        if (this.size != null) {
            size = this.size.clone();
        }
        return size;
    },

    /**
     * APIMethod: updateSize
     * This function should be called by any external code which dynamically
     *     changes the size of the map div (because mozilla wont let us catch 
     *     the "onresize" for an element)
     */
    updateSize: function() {
        // the div might have moved on the page, also
        this.events.element.offsets = null;
        var newSize = this.getCurrentSize();
        var oldSize = this.getSize();
        if (oldSize == null)
            this.size = oldSize = newSize;
        if (!newSize.equals(oldSize)) {
            
            // store the new size
            this.size = newSize;

            //notify layers of mapresize
            for(var i=0; i < this.layers.length; i++) {
                this.layers[i].onMapResize();                
            }

            if (this.baseLayer != null) {
                var center = new OpenLayers.Pixel(newSize.w /2, newSize.h / 2);
                var centerLL = this.getLonLatFromViewPortPx(center);
                var zoom = this.getZoom();
                this.zoom = null;
                this.setCenter(this.getCenter(), zoom);
            }

        }
    },
    
    /**
     * Method: getCurrentSize
     * 
     * Returns:
     * {<OpenLayers.Size>} A new <OpenLayers.Size> object with the dimensions 
     *                     of the map div
     */
    getCurrentSize: function() {

        var size = new OpenLayers.Size(this.div.clientWidth, 
                                       this.div.clientHeight);

        // Workaround for the fact that hidden elements return 0 for size.
        if (size.w == 0 && size.h == 0 || isNaN(size.w) && isNaN(size.h)) {
            var dim = OpenLayers.Element.getDimensions(this.div);
            size.w = dim.width;
            size.h = dim.height;
        }
        if (size.w == 0 && size.h == 0 || isNaN(size.w) && isNaN(size.h)) {
            size.w = parseInt(this.div.style.width);
            size.h = parseInt(this.div.style.height);
        }
        return size;
    },

    /** 
     * Method: calculateBounds
     * 
     * Parameters:
     * center - {<OpenLayers.LonLat>} Default is this.getCenter()
     * resolution - {float} Default is this.getResolution() 
     * 
     * Returns:
     * {<OpenLayers.Bounds>} A bounds based on resolution, center, and 
     *                       current mapsize.
     */
    calculateBounds: function(center, resolution) {

        var extent = null;
        
        if (center == null) {
            center = this.getCenter();
        }                
        if (resolution == null) {
            resolution = this.getResolution();
        }
    
        if ((center != null) && (resolution != null)) {

            var size = this.getSize();
            var w_deg = size.w * resolution;
            var h_deg = size.h * resolution;
        
            extent = new OpenLayers.Bounds(center.lon - w_deg / 2,
                                           center.lat - h_deg / 2,
                                           center.lon + w_deg / 2,
                                           center.lat + h_deg / 2);
        
        }

        return extent;
    },


  /********************************************************/
  /*                                                      */
  /*            Zoom, Center, Pan Functions               */
  /*                                                      */
  /*    The following functions handle the validation,    */
  /*   getting and setting of the Zoom Level and Center   */
  /*       as well as the panning of the Map              */
  /*                                                      */
  /********************************************************/
    /**
     * APIMethod: getCenter
     * 
     * Returns:
     * {<OpenLayers.LonLat>}
     */
    getCenter: function () {
        return this.center;
    },


    /**
     * APIMethod: getZoom
     * 
     * Returns:
     * {Integer}
     */
    getZoom: function () {
        return this.zoom;
    },
    
    /** 
     * APIMethod: pan
     * Allows user to pan by a value of screen pixels
     * 
     * Parameters:
     * dx - {Integer}
     * dy - {Integer}
     */
    pan: function(dx, dy) {

        // getCenter
        var centerPx = this.getViewPortPxFromLonLat(this.getCenter());

        // adjust
        var newCenterPx = centerPx.add(dx, dy);
        
        // only call setCenter if there has been a change
        if (!newCenterPx.equals(centerPx)) {
            var newCenterLonLat = this.getLonLatFromViewPortPx(newCenterPx);
            this.setCenter(newCenterLonLat);
        }

   },

    /**
     * APIMethod: setCenter
     * 
     * Parameters:
     * lonlat - {<OpenLayers.LonLat>}
     * zoom - {Integer}
     * dragging - {Boolean} Specifies whether or not to trigger 
     *                      movestart/end events
     * forceZoomChange - {Boolean} Specifies whether or not to trigger zoom 
     *                             change events (needed on baseLayer change)
     *
     * TBD: reconsider forceZoomChange in 3.0
     */
    setCenter: function (lonlat, zoom, dragging, forceZoomChange) {

        if (!this.center && !this.isValidLonLat(lonlat)) {
            lonlat = this.maxExtent.getCenterLonLat();
        }

        if(this.restrictedExtent != null) {
            // In 3.0, decide if we want to change interpretation of maxExtent.
            if(lonlat == null) { 
                lonlat = this.getCenter(); 
            }
            if(zoom == null) { 
                zoom = this.getZoom(); 
            }
            var resolution = null;
            if(this.baseLayer != null) {
                resolution = this.baseLayer.resolutions[zoom];
            }
            var extent = this.calculateBounds(lonlat, resolution); 
            if(!this.restrictedExtent.containsBounds(extent)) {
                var maxCenter = this.restrictedExtent.getCenterLonLat(); 
                if(extent.getWidth() > this.restrictedExtent.getWidth()) { 
                    lonlat = new OpenLayers.LonLat(maxCenter.lon, lonlat.lat); 
                } else if(extent.left < this.restrictedExtent.left) {
                    lonlat = lonlat.add(this.restrictedExtent.left -
                                        extent.left, 0); 
                } else if(extent.right > this.restrictedExtent.right) { 
                    lonlat = lonlat.add(this.restrictedExtent.right -
                                        extent.right, 0); 
                } 
                if(extent.getHeight() > this.restrictedExtent.getHeight()) { 
                    lonlat = new OpenLayers.LonLat(lonlat.lon, maxCenter.lat); 
                } else if(extent.bottom < this.restrictedExtent.bottom) { 
                    lonlat = lonlat.add(0, this.restrictedExtent.bottom -
                                        extent.bottom); 
                } 
                else if(extent.top > this.restrictedExtent.top) { 
                    lonlat = lonlat.add(0, this.restrictedExtent.top -
                                        extent.top); 
                } 
            }
        }
        
        var zoomChanged = forceZoomChange || (
                            (this.isValidZoomLevel(zoom)) && 
                            (zoom != this.getZoom()) );

        var centerChanged = (this.isValidLonLat(lonlat)) && 
                            (!lonlat.equals(this.center));


        // if neither center nor zoom will change, no need to do anything
        if (zoomChanged || centerChanged || !dragging) {

            if (!dragging) { this.events.triggerEvent("movestart"); }

            if (centerChanged) {
                if ((!zoomChanged) && (this.center)) { 
                    // if zoom hasnt changed, just slide layerContainer
                    //  (must be done before setting this.center to new value)
                    this.centerLayerContainer(lonlat);
                }
                this.center = lonlat.clone();
            }

            // (re)set the layerContainerDiv's location
            if ((zoomChanged) || (this.layerContainerOrigin == null)) {
                this.layerContainerOrigin = this.center.clone();
                this.layerContainerDiv.style.left = "0px";
                this.layerContainerDiv.style.top  = "0px";
            }

            if (zoomChanged) {
                this.zoom = zoom;
                // zoom level has changed, increment viewRequestID.
                this.viewRequestID++;
            }    
            
            var bounds = this.getExtent();
            
            //send the move call to the baselayer and all the overlays    
            this.baseLayer.moveTo(bounds, zoomChanged, dragging);
            
            bounds = this.baseLayer.getExtent();
            
            for (var i = 0; i < this.layers.length; i++) {
                var layer = this.layers[i];
                if (!layer.isBaseLayer) {
                    
                    var moveLayer;
                    var inRange = layer.calculateInRange();
                    if (layer.inRange != inRange) {
                        // Layer property has changed. We are going 
                        // to call moveLayer so that the layer can be turned
                        // off or on.   
                        layer.inRange = inRange;
                        moveLayer = true;
                        this.events.triggerEvent("changelayer");
                    } else {
                        // If nothing has changed, then we only move the layer
                        // if it is visible and inrange.
                        moveLayer = (layer.visibility && layer.inRange);
                    }

                    if (moveLayer) {
                        layer.moveTo(bounds, zoomChanged, dragging);
                    }
                }                
            }
            
            if (zoomChanged) {
                //redraw popups
                for (var i = 0; i < this.popups.length; i++) {
                    this.popups[i].updatePosition();
                }
            }    
            
            this.events.triggerEvent("move");
    
            if (zoomChanged) { this.events.triggerEvent("zoomend"); }
        }

        // even if nothing was done, we want to notify of this
        if (!dragging) { this.events.triggerEvent("moveend"); }
    },

    /** 
     * Method: centerLayerContainer
     * This function takes care to recenter the layerContainerDiv.
     * 
     * Parameters:
     * lonlat - {<OpenLayers.LonLat>}
     */
    centerLayerContainer: function (lonlat) {

        var originPx = this.getViewPortPxFromLonLat(this.layerContainerOrigin);
        var newPx = this.getViewPortPxFromLonLat(lonlat);

        if ((originPx != null) && (newPx != null)) {
            this.layerContainerDiv.style.left = (originPx.x - newPx.x) + "px";
            this.layerContainerDiv.style.top  = (originPx.y - newPx.y) + "px";
        }
    },

    /**
     * Method: isValidZoomLevel
     * 
     * Parameters:
     * zoomLevel - {Integer}
     * 
     * Returns:
     * {Boolean} Whether or not the zoom level passed in is non-null and 
     *           within the min/max range of zoom levels.
     */
    isValidZoomLevel: function(zoomLevel) {
       return ( (zoomLevel != null) &&
                (zoomLevel >= 0) && 
                (zoomLevel < this.getNumZoomLevels()) );
    },
    
    /**
     * Method: isValidLonLat
     * 
     * Parameters:
     * lonlat - {<OpenLayers.LonLat>}
     * 
     * Returns:
     * {Boolean} Whether or not the lonlat passed in is non-null and within
     *           the maxExtent bounds
     */
    isValidLonLat: function(lonlat) {
        var valid = false;
        if (lonlat != null) {
            var maxExtent = this.getMaxExtent();
            valid = maxExtent.containsLonLat(lonlat);        
        }
        return valid;
    },

  /********************************************************/
  /*                                                      */
  /*                 Layer Options                        */
  /*                                                      */
  /*    Accessor functions to Layer Options parameters    */
  /*                                                      */
  /********************************************************/
    
    /**
     * APIMethod: getProjection
     * 
     * Returns:
     * {String} The Projection of the base layer.
     */
    getProjection: function() {
        var projection = null;
        if (this.baseLayer != null) {
            projection = this.baseLayer.projection;
        }
        return projection;
    },
    
    /**
     * APIMethod: getMaxResolution
     * 
     * Returns:
     * {String} The Map's Maximum Resolution
     */
    getMaxResolution: function() {
        var maxResolution = null;
        if (this.baseLayer != null) {
            maxResolution = this.baseLayer.maxResolution;
        }
        return maxResolution;
    },
        
    /**
     * APIMethod: getMaxExtent
     * 
     * Returns:
     * {<OpenLayers.Bounds>}