--- a/labs/openlayers/lib/OpenLayers/Layer.js
+++ b/labs/openlayers/lib/OpenLayers/Layer.js
@@ -1,1 +1,1305 @@
-
+/* 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/Map.js
+ * @requires OpenLayers/Projection.js
+ */
+
+/**
+ * Class: OpenLayers.Layer
+ */
+OpenLayers.Layer = OpenLayers.Class({
+
+    /**
+     * APIProperty: id
+     * {String}
+     */
+    id: null,
+
+    /** 
+     * APIProperty: name
+     * {String}
+     */
+    name: null,
+
+    /** 
+     * APIProperty: div
+     * {DOMElement}
+     */
+    div: null,
+
+    /**
+     * Property: opacity
+     * {Float} The layer's opacity. Float number between 0.0 and 1.0.
+     */
+    opacity: null,
+
+    /**
+     * APIProperty: alwaysInRange
+     * {Boolean} If a layer's display should not be scale-based, this should 
+     *     be set to true. This will cause the layer, as an overlay, to always 
+     *     be 'active', by always returning true from the calculateInRange() 
+     *     function. 
+     * 
+     *     If not explicitly specified for a layer, its value will be 
+     *     determined on startup in initResolutions() based on whether or not 
+     *     any scale-specific properties have been set as options on the 
+     *     layer. If no scale-specific options have been set on the layer, we 
+     *     assume that it should always be in range.
+     * 
+     *     See #987 for more info.
+     */
+    alwaysInRange: null,   
+
+    /**
+     * Constant: EVENT_TYPES
+     * {Array(String)} Supported application event types.  Register a listener
+     *     for a particular event with the following syntax:
+     * (code)
+     * layer.events.register(type, obj, listener);
+     * (end)
+     *
+     * Listeners will be called with a reference to an event object.  The
+     *     properties of this event depends on exactly what happened.
+     *
+     * All event objects have at least the following properties:
+     * object - {Object} A reference to layer.events.object.
+     * element - {DOMElement} A reference to layer.events.element.
+     *
+     * Supported map event types:
+     * loadstart - Triggered when layer loading starts.
+     * loadend - Triggered when layer loading ends.
+     * loadcancel - Triggered when layer loading is canceled.
+     * visibilitychanged - Triggered when layer visibility is changed.
+     * move - Triggered when layer moves (triggered with every mousemove
+     *     during a drag).
+     * moveend - Triggered when layer is done moving, object passed as
+     *     argument has a zoomChanged boolean property which tells that the
+     *     zoom has changed.
+     */
+    EVENT_TYPES: ["loadstart", "loadend", "loadcancel", "visibilitychanged",
+                  "move", "moveend"],
+
+    /**
+     * Constant: RESOLUTION_PROPERTIES
+     * {Array} The properties that are used for calculating resolutions
+     *     information.
+     */
+    RESOLUTION_PROPERTIES: [
+        'scales', 'resolutions',
+        'maxScale', 'minScale',
+        'maxResolution', 'minResolution',
+        'numZoomLevels', 'maxZoomLevel'
+    ],
+
+    /**
+     * APIProperty: events
+     * {<OpenLayers.Events>}
+     */
+    events: null,
+
+    /**
+     * APIProperty: map
+     * {<OpenLayers.Map>} This variable is set when the layer is added to 
+     *     the map, via the accessor function setMap().
+     */
+    map: null,
+    
+    /**
+     * APIProperty: isBaseLayer
+     * {Boolean} Whether or not the layer is a base layer. This should be set 
+     *     individually by all subclasses. Default is false
+     */
+    isBaseLayer: false,
+ 
+    /**
+     * Property: alpha
+     * {Boolean} The layer's images have an alpha channel.  Default is false. 
+     */
+    alpha: false,
+
+    /** 
+     * APIProperty: displayInLayerSwitcher
+     * {Boolean} Display the layer's name in the layer switcher.  Default is
+     *     true.
+     */
+    displayInLayerSwitcher: true,
+
+    /**
+     * APIProperty: visibility
+     * {Boolean} The layer should be displayed in the map.  Default is true.
+     */
+    visibility: true,
+
+    /**
+     * APIProperty: attribution
+     * {String} Attribution string, displayed when an 
+     *     <OpenLayers.Control.Attribution> has been added to the map.
+     */
+    attribution: null, 
+
+    /** 
+     * Property: inRange
+     * {Boolean} The current map resolution is within the layer's min/max 
+     *     range. This is set in <OpenLayers.Map.setCenter> whenever the zoom 
+     *     changes.
+     */
+    inRange: false,
+    
+    /**
+     * Propery: imageSize
+     * {<OpenLayers.Size>} For layers with a gutter, the image is larger than 
+     *     the tile by twice the gutter in each dimension.
+     */
+    imageSize: null,
+    
+    /**
+     * Property: imageOffset
+     * {<OpenLayers.Pixel>} For layers with a gutter, the image offset 
+     *     represents displacement due to the gutter.
+     */
+    imageOffset: null,
+
+  // OPTIONS
+
+    /** 
+     * Property: options
+     * {Object} An optional object whose properties will be set on the layer.
+     *     Any of the layer properties can be set as a property of the options
+     *     object and sent to the constructor when the layer is created.
+     */
+    options: null,
+
+    /**
+     * APIProperty: eventListeners
+     * {Object} If set as an option at construction, the eventListeners
+     *     object will be registered with <OpenLayers.Events.on>.  Object
+     *     structure must be a listeners object as shown in the example for
+     *     the events.on method.
+     */
+    eventListeners: null,
+
+    /**
+     * APIProperty: gutter
+     * {Integer} Determines the width (in pixels) of the gutter around image
+     *     tiles to ignore.  By setting this property to a non-zero value,
+     *     images will be requested that are wider and taller than the tile
+     *     size by a value of 2 x gutter.  This allows artifacts of rendering
+     *     at tile edges to be ignored.  Set a gutter value that is equal to
+     *     half the size of the widest symbol that needs to be displayed.
+     *     Defaults to zero.  Non-tiled layers always have zero gutter.
+     */ 
+    gutter: 0, 
+
+    /**
+     * APIProperty: projection
+     * {<OpenLayers.Projection>} or {<String>} Set in the layer options to
+     *     override the default projection string this layer - also set maxExtent,
+     *     maxResolution, and units if appropriate. Can be either a string or
+     *     an <OpenLayers.Projection> object when created -- will be converted
+     *     to an object when setMap is called if a string is passed.  
+     */
+    projection: null,    
+    
+    /**
+     * APIProperty: units
+     * {String} The layer map units.  Defaults to 'degrees'.  Possible values
+     *     are 'degrees' (or 'dd'), 'm', 'ft', 'km', 'mi', 'inches'.
+     */
+    units: null,
+
+    /**
+     * APIProperty: scales
+     * {Array}  An array of map scales in descending order.  The values in the
+     *     array correspond to the map scale denominator.  Note that these
+     *     values only make sense if the display (monitor) resolution of the
+     *     client is correctly guessed by whomever is configuring the
+     *     application.  In addition, the units property must also be set.
+     *     Use <resolutions> instead wherever possible.
+     */
+    scales: null,
+
+    /**
+     * APIProperty: resolutions
+     * {Array} A list of map resolutions (map units per pixel) in descending
+     *     order.  If this is not set in the layer constructor, it will be set
+     *     based on other resolution related properties (maxExtent,
+     *     maxResolution, maxScale, etc.).
+     */
+    resolutions: null,
+    
+    /**
+     * APIProperty: maxExtent
+     * {<OpenLayers.Bounds>}  The center of these bounds will not stray outside
+     *     of the viewport extent during panning.  In addition, if
+     *     <displayOutsideMaxExtent> is set to false, data will not be
+     *     requested that falls completely outside of these bounds.
+     */
+    maxExtent: null,
+    
+    /**
+     * APIProperty: minExtent
+     * {<OpenLayers.Bounds>}
+     */
+    minExtent: null,
+    
+    /**
+     * APIProperty: maxResolution
+     * {Float} Default max is 360 deg / 256 px, which corresponds to
+     *     zoom level 0 on gmaps.  Specify a different value in the layer 
+     *     options if you are not using a geographic projection and 
+     *     displaying the whole world.
+     */
+    maxResolution: null,
+
+    /**
+     * APIProperty: minResolution
+     * {Float}
+     */
+    minResolution: null,
+
+    /**
+     * APIProperty: numZoomLevels
+     * {Integer}
+     */
+    numZoomLevels: null,
+   
+    /**
+     * APIProperty: minScale
+     * {Float}
+     */
+    minScale: null,
+    
+    /**
+     * APIProperty: maxScale
+     * {Float}
+     */
+    maxScale: null,
+
+    /**
+     * APIProperty: displayOutsideMaxExtent
+     * {Boolean} Request map tiles that are completely outside of the max 
+     *     extent for this layer. Defaults to false.
+     */
+    displayOutsideMaxExtent: false,
+
+    /**
+     * APIProperty: wrapDateLine
+     * {Boolean} #487 for more info.   
+     */
+    wrapDateLine: false,
+    
+    /**
+     * APIProperty: transitionEffect
+     * {String} The transition effect to use when the map is panned or
+     *     zoomed.  
+     *
+     * There are currently two supported values:
+     *  - *null* No transition effect (the default).
+     *  - *resize*  Existing tiles are resized on zoom to provide a visual
+     *    effect of the zoom having taken place immediately.  As the
+     *    new tiles become available, they are drawn over top of the
+     *    resized tiles.
+     */
+    transitionEffect: null,
+    
+    /**
+     * Property: SUPPORTED_TRANSITIONS
+     * {Array} An immutable (that means don't change it!) list of supported 
+     *     transitionEffect values.
+     */
+    SUPPORTED_TRANSITIONS: ['resize'],
+
+    /**
+     * Property: metadata
+     * {Object} This object can be used to store additional information on a
+     *     layer object.
+     */
+    metadata: {},
+    
+    /**
+     * Constructor: OpenLayers.Layer
+     *
+     * Parameters:
+     * name - {String} The layer name
+     * options - {Object} Hashtable of extra options to tag onto the layer
+     */
+    initialize: function(name, options) {
+
+        this.addOptions(options);
+
+        this.name = name;
+        
+        if (this.id == null) {
+
+            this.id = OpenLayers.Util.createUniqueID(this.CLASS_NAME + "_");
+
+            this.div = OpenLayers.Util.createDiv(this.id);
+            this.div.style.width = "100%";
+            this.div.style.height = "100%";
+            this.div.dir = "ltr";
+
+            this.events = new OpenLayers.Events(this, this.div, 
+                                                this.EVENT_TYPES);
+            if(this.eventListeners instanceof Object) {
+                this.events.on(this.eventListeners);
+            }
+
+        }
+
+        if (this.wrapDateLine) {
+            this.displayOutsideMaxExtent = true;
+        }
+    },
+    
+    /**
+     * Method: destroy
+     * Destroy is a destructor: this is to alleviate cyclic references which
+     *     the Javascript garbage cleaner can not take care of on its own.
+     *
+     * Parameters:
+     * setNewBaseLayer - {Boolean} Set a new base layer when this layer has
+     *     been destroyed.  Default is true.
+     */
+    destroy: function(setNewBaseLayer) {
+        if (setNewBaseLayer == null) {
+            setNewBaseLayer = true;
+        }
+        if (this.map != null) {
+            this.map.removeLayer(this, setNewBaseLayer);
+        }
+        this.projection = null;
+        this.map = null;
+        this.name = null;
+        this.div = null;
+        this.options = null;
+
+        if (this.events) {
+            if(this.eventListeners) {
+                this.events.un(this.eventListeners);
+            }
+            this.events.destroy();
+        }
+        this.eventListeners = null;
+        this.events = null;
+    },
+    
+   /**
+    * Method: clone
+    *
+    * Parameters:
+    * obj - {<OpenLayers.Layer>} The layer to be cloned
+    *
+    * Returns:
+    * {<OpenLayers.Layer>} An exact clone of this <OpenLayers.Layer>
+    */
+    clone: function (obj) {
+        
+        if (obj == null) {
+            obj = new OpenLayers.Layer(this.name, this.getOptions());
+        }
+        
+        // catch any randomly tagged-on properties
+        OpenLayers.Util.applyDefaults(obj, this);
+        
+        // a cloned layer should never have its map property set
+        //  because it has not been added to a map yet. 
+        obj.map = null;
+        
+        return obj;
+    },
+    
+    /**
+     * Method: getOptions
+     * Extracts an object from the layer with the properties that were set as
+     *     options, but updates them with the values currently set on the
+     *     instance.
+     * 
+     * Returns:
+     * {Object} the <options> of the layer, representing the current state.
+     */
+    getOptions: function() {
+        var options = {};
+        for(var o in this.options) {
+            options[o] = this[o];
+        }
+        return options;
+    },
+    
+    /** 
+     * APIMethod: setName
+     * Sets the new layer name for this layer.  Can trigger a changelayer event
+     *     on the map.
+     *
+     * Parameters:
+     * newName - {String} The new name.
+     */
+    setName: function(newName) {
+        if (newName != this.name) {
+            this.name = newName;
+            if (this.map != null) {
+                this.map.events.triggerEvent("changelayer", {
+                    layer: this,
+                    property: "name"
+                });
+            }
+        }
+    },    
+    
+   /**
+    * APIMethod: addOptions
+    * 
+    * Parameters:
+    * newOptions - {Object}
+    */
+    addOptions: function (newOptions) {
+
+        if (this.options == null) {
+            this.options = {};
+        }
+
+        // update our copy for clone
+        OpenLayers.Util.extend(this.options, newOptions);
+
+        // add new options to this
+        OpenLayers.Util.extend(this, newOptions);
+
+        // make sure this.projection references a projection object
+        if(typeof this.projection == "string") {
+            this.projection = new OpenLayers.Projection(this.projection);
+        }
+
+        // get the units from the projection, if we have a projection
+        // and it it has units
+        if(this.projection && this.projection.getUnits()) {
+            this.units = this.projection.getUnits();
+        }
+
+        // re-initialize resolutions if necessary, i.e. if any of the
+        // properties of the "properties" array defined below is set
+        // in the new options
+        if(this.map) {
+            var properties = this.RESOLUTION_PROPERTIES.concat(
+                ["projection", "units", "minExtent", "maxExtent"]
+            );
+            for(var o in newOptions) {
+                if(newOptions.hasOwnProperty(o) &&
+                   OpenLayers.Util.indexOf(properties, o) >= 0) {
+
+                    this.initResolutions();
+                    break;
+                }
+            }
+        }
+    },
+
+    /**
+     * APIMethod: onMapResize
+     * This function can be implemented by subclasses
+     */
+    onMapResize: function() {
+        //this function can be implemented by subclasses  
+    },
+
+    /**
+     * APIMethod: redraw
+     * Redraws the layer.  Returns true if the layer was redrawn, false if not.
+     *
+     * Returns:
+     * {Boolean} The layer was redrawn.
+     */
+    redraw: function() {
+        var redrawn = false;
+        if (this.map) {
+
+            // min/max Range may have changed
+            this.inRange = this.calculateInRange();
+
+            // map's center might not yet be set
+            var extent = this.getExtent();
+
+            if (extent && this.inRange && this.visibility) {
+                var zoomChanged = true;
+                this.moveTo(extent, zoomChanged, false);
+                this.events.triggerEvent("moveend",
+                    {"zoomChanged": zoomChanged});
+                redrawn = true;
+            }
+        }
+        return redrawn;
+    },
+
+    /**
+     * Method: moveTo
+     * 
+     * Parameters:
+     * bound - {<OpenLayers.Bounds>}
+     * zoomChanged - {Boolean} Tells when zoom has changed, as layers have to
+     *     do some init work in that case.
+     * dragging - {Boolean}
+     */
+    moveTo:function(bounds, zoomChanged, dragging) {
+        var display = this.visibility;
+        if (!this.isBaseLayer) {
+            display = display && this.inRange;
+        }
+        this.display(display);
+    },
+
+    /**
+     * Method: setMap
+     * Set the map property for the layer. This is done through an accessor
+     *     so that subclasses can override this and take special action once 
+     *     they have their map variable set. 
+     * 
+     *     Here we take care to bring over any of the necessary default 
+     *     properties from the map. 
+     * 
+     * Parameters:
+     * map - {<OpenLayers.Map>}
+     */
+    setMap: function(map) {
+        if (this.map == null) {
+        
+            this.map = map;
+            
+            // grab some essential layer data from the map if it hasn't already
+            //  been set
+            this.maxExtent = this.maxExtent || this.map.maxExtent;
+            this.minExtent = this.minExtent || this.map.minExtent;
+
+            this.projection = this.projection || this.map.projection;
+            if (typeof this.projection == "string") {
+                this.projection = new OpenLayers.Projection(this.projection);
+            }
+
+            // Check the projection to see if we can get units -- if not, refer
+            // to properties.
+            this.units = this.projection.getUnits() ||
+                         this.units || this.map.units;
+            
+            this.initResolutions();
+            
+            if (!this.isBaseLayer) {
+                this.inRange = this.calculateInRange();
+                var show = ((this.visibility) && (this.inRange));
+                this.div.style.display = show ? "" : "none";
+            }
+            
+            // deal with gutters
+            this.setTileSize();
+        }
+    },
+    
+    /**
+     * Method: afterAdd
+     * Called at the end of the map.addLayer sequence.  At this point, the map
+     *     will have a base layer.  To be overridden by subclasses.
+     */
+    afterAdd: function() {
+    },
+    
+    /**
+     * APIMethod: removeMap
+     * Just as setMap() allows each layer the possibility to take a 
+     *     personalized action on being added to the map, removeMap() allows
+     *     each layer to take a personalized action on being removed from it. 
+     *     For now, this will be mostly unused, except for the EventPane layer,
+     *     which needs this hook so that it can remove the special invisible
+     *     pane. 
+     * 
+     * Parameters:
+     * map - {<OpenLayers.Map>}
+     */
+    removeMap: function(map) {
+        //to be overridden by subclasses
+    },
+    
+    /**
+     * APIMethod: getImageSize
+     *
+     * Parameters:
+     * bounds - {<OpenLayers.Bounds>} optional tile bounds, can be used
+     *     by subclasses that have to deal with different tile sizes at the
+     *     layer extent edges (e.g. Zoomify)
+     * 
+     * Returns:
+     * {<OpenLayers.Size>} The size that the image should be, taking into 
+     *     account gutters.
+     */ 
+    getImageSize: function(bounds) { 
+        return (this.imageSize || this.tileSize); 
+    },    
+  
+    /**
+     * APIMethod: setTileSize
+     * Set the tile size based on the map size.  This also sets layer.imageSize
+     *     and layer.imageOffset for use by Tile.Image.
+     * 
+     * Parameters:
+     * size - {<OpenLayers.Size>}
+     */
+    setTileSize: function(size) {
+        var tileSize = (size) ? size :
+                                ((this.tileSize) ? this.tileSize :
+                                                   this.map.getTileSize());
+        this.tileSize = tileSize;
+        if(this.gutter) {
+          // layers with gutters need non-null tile sizes
+          //if(tileSize == null) {
+          //    OpenLayers.console.error("Error in layer.setMap() for " +
+          //                              this.name + ": layers with " +
+          //                              "gutters need non-null tile sizes");
+          //}
+            this.imageOffset = new OpenLayers.Pixel(-this.gutter, 
+                                                    -this.gutter); 
+            this.imageSize = new OpenLayers.Size(tileSize.w + (2*this.gutter), 
+                                                 tileSize.h + (2*this.gutter)); 
+        }
+    },
+
+    /**
+     * APIMethod: getVisibility
+     * 
+     * Returns:
+     * {Boolean} The layer should be displayed (if in range).
+     */
+    getVisibility: function() {
+        return this.visibility;
+    },
+
+    /** 
+     * APIMethod: setVisibility
+     * Set the visibility flag for the layer and hide/show & redraw 
+     *     accordingly. Fire event unless otherwise specified
+     * 
+     * Note that visibility is no longer simply whether or not the layer's
+     *     style.display is set to "block". Now we store a 'visibility' state 
+     *     property on the layer class, this allows us to remember whether or 
+     *     not we *desire* for a layer to be visible. In the case where the 
+     *     map's resolution is out of the layer's range, this desire may be 
+     *     subverted.
+     * 
+     * Parameters:
+     * visible - {Boolean} Whether or not to display the layer (if in range)
+     */
+    setVisibility: function(visibility) {
+        if (visibility != this.visibility) {
+            this.visibility = visibility;
+            this.display(visibility);
+            this.redraw();
+            if (this.map != null) {
+                this.map.events.triggerEvent("changelayer", {
+                    layer: this,
+                    property: "visibility"
+                });
+            }
+            this.events.triggerEvent("visibilitychanged");
+        }
+    },
+
+    /** 
+     * APIMethod: display
+     * Hide or show the Layer
+     * 
+     * Parameters:
+     * display - {Boolean}
+     */
+    display: function(display) {
+        if (display != (this.div.style.display != "none")) {
+            this.div.style.display = (display && this.calculateInRange()) ? "block" : "none";
+        }
+    },
+
+    /**
+     * APIMethod: calculateInRange
+     * 
+     * Returns:
+     * {Boolean} The layer is displayable at the current map's current
+     *     resolution. Note that if 'alwaysInRange' is true for the layer, 
+     *     this function will always return true.
+     */
+    calculateInRange: function() {
+        var inRange = false;
+
+        if (this.alwaysInRange) {
+            inRange = true;
+        } else {
+            if (this.map) {
+                var resolution = this.map.getResolution();
+                inRange = ( (resolution >= this.minResolution) &&
+                            (resolution <= this.maxResolution) );
+            }
+        }
+        return inRange;
+    },
+
+    /** 
+     * APIMethod: setIsBaseLayer
+     * 
+     * Parameters:
+     * isBaseLayer - {Boolean}
+     */
+    setIsBaseLayer: function(isBaseLayer) {
+        if (isBaseLayer != this.isBaseLayer) {
+            this.isBaseLayer = isBaseLayer;
+            if (this.map != null) {
+                this.map.events.triggerEvent("changebaselayer", {
+                    layer: this
+                });
+            }
+        }
+    },
+
+  /********************************************************/
+  /*                                                      */
+  /*                 Baselayer Functions                  */
+  /*                                                      */
+  /********************************************************/
+  
+    /** 
+     * Method: initResolutions
+     * This method's responsibility is to set up the 'resolutions' array 
+     *     for the layer -- this array is what the layer will use to interface
+     *     between the zoom levels of the map and the resolution display 
+     *     of the layer.
+     * 
+     * The user has several options that determine how the array is set up.
+     *  
+     * For a detailed explanation, see the following wiki from the 
+     *     openlayers.org homepage:
+     *     http://trac.openlayers.org/wiki/SettingZoomLevels
+     */
+    initResolutions: function() {
+
+        // ok we want resolutions, here's our strategy:
+        //
+        // 1. if resolutions are defined in the layer config, use them
+        // 2. else, if scales are defined in the layer config then derive
+        //    resolutions from these scales
+        // 3. else, attempt to calculate resolutions from maxResolution,
+        //    minResolution, numZoomLevels, maxZoomLevel set in the
+        //    layer config
+        // 4. if we still don't have resolutions, and if resolutions
+        //    are defined in the same, use them
+        // 5. else, if scales are defined in the map then derive
+        //    resolutions from these scales
+        // 6. else, attempt to calculate resolutions from maxResolution,
+        //    minResolution, numZoomLevels, maxZoomLevel set in the
+        //    map
+        // 7. hope for the best!
+
+        var i, len;
+        var props = {}, alwaysInRange = true;
+
+        // get resolution data from layer config
+        // (we also set alwaysInRange in the layer as appropriate)
+        for(i=0, len=this.RESOLUTION_PROPERTIES.length; i<len; i++) {
+            var p = this.RESOLUTION_PROPERTIES[i];
+            props[p] = this.options[p];
+            if(alwaysInRange && this.options[p]) {
+                alwaysInRange = false;
+            }
+        }
+        if(this.alwaysInRange == null) {
+            this.alwaysInRange = alwaysInRange;
+        }
+
+        // if we don't have resolutions then attempt to derive them from scales
+        if(props.resolutions == null) {
+            props.resolutions = this.resolutionsFromScales(props.scales);
+        }
+
+        // if we still don't have resolutions then attempt to calculate them
+        if(props.resolutions == null) {
+            props.resolutions = this.calculateResolutions(props);
+        }
+
+        // if we couldn't calculate resolutions then we look at we have
+        // in the map
+        if(props.resolutions == null) {
+            for(i=0, len=this.RESOLUTION_PROPERTIES.length; i<len; i++) {
+                var p = this.RESOLUTION_PROPERTIES[i];
+                props[p] = this.options[p] != null ?
+                    this.options[p] : this.map[p];
+            }
+            if(props.resolutions == null) {
+                props.resolutions = this.resolutionsFromScales(props.scales);
+            }
+            if(props.resolutions == null) {
+                props.resolutions = this.calculateResolutions(props);
+            }
+        }
+
+        // ok, we new need to set properties in the instance
+
+        // get maxResolution from the config if it's defined there
+        var maxResolution;
+        if(this.options.maxResolution &&
+           this.options.maxResolution !== "auto") {
+            maxResolution = this.options.maxResolution;
+        }
+        if(this.options.minScale) {
+            maxResolution = OpenLayers.Util.getResolutionFromScale(
+                this.options.minScale, this.units);
+        }
+
+        // get minResolution from the config if it's defined there
+        var minResolution;
+        if(this.options.minResolution &&
+           this.options.minResolution !== "auto") {
+            minResolution = this.options.minResolution;
+        }
+        if(this.options.maxScale) {
+            minResolution = OpenLayers.Util.getResolutionFromScale(
+                this.options.maxScale, this.units);
+        }
+
+        if(props.resolutions) {
+
+            //sort resolutions array descendingly
+            props.resolutions.sort(function(a, b) {
+                return (b - a);
+            });
+
+            // if we still don't have a maxResolution get it from the
+            // resolutions array
+            if(!maxResolution) {
+                maxResolution = props.resolutions[0];
+            }
+
+            // if we still don't have a minResolution get it from the
+            // resolutions array
+            if(!minResolution) {
+                var lastIdx = props.resolutions.length - 1;
+                minResolution = props.resolutions[lastIdx];
+            }
+        }
+
+        this.resolutions = props.resolutions;
+        if(this.resolutions) {
+            len = this.resolutions.length;
+            this.scales = new Array(len);
+            for(i=0; i<len; i++) {
+                this.scales[i] = OpenLayers.Util.getScaleFromResolution(
+                    this.resolutions[i], this.units);
+            }
+            this.numZoomLevels = len;
+        }
+        this.minResolution = minResolution;
+        if(minResolution) {
+            this.maxScale = OpenLayers.Util.getScaleFromResolution(
+                minResolution, this.units);
+        }
+        this.maxResolution = maxResolution;
+        if(maxResolution) {
+            this.minScale = OpenLayers.Util.getScaleFromResolution(
+                maxResolution, this.units);
+        }
+    },
+
+    /**
+     * Method: resolutionsFromScales
+     * Derive resolutions from scales.
+     *
+     * Parameters:
+     * scales - {Array(Number)} Scales
+     *
+     * Returns
+     * {Array(Number)} Resolutions
+     */
+    resolutionsFromScales: function(scales) {
+        if(scales == null) {
+            return;
+        }
+        var resolutions, i, len;
+        len = scales.length;
+        resolutions = new Array(len);
+        for(i=0; i<len; i++) {
+            resolutions[i] = OpenLayers.Util.getResolutionFromScale(
+                scales[i], this.units);
+        }
+        return resolutions;
+    },
+
+    /**
+     * Method: calculateResolutions
+     * Calculate resolutions based on the provided properties.
+     *
+     * Parameters:
+     * props - {Object} Properties
+     *
+     * Return:
+     * {Array({Number})} Array of resolutions.
+     */
+    calculateResolutions: function(props) {
+
+        // determine maxResolution
+        var maxResolution = props.maxResolution;
+        if(props.minScale != null) {
+            maxResolution =
+                OpenLayers.Util.getResolutionFromScale(props.minScale,
+                                                       this.units);
+        } else if(maxResolution == "auto" && this.maxExtent != null) {
+            var viewSize = this.map.getSize();
+            var wRes = this.maxExtent.getWidth() / viewSize.w;
+            var hRes = this.maxExtent.getHeight() / viewSize.h;
+            maxResolution = Math.max(wRes, hRes);
+        }
+
+        // determine minResolution
+        var minResolution = props.minResolution;
+        if(props.maxScale != null) {
+            minResolution =
+                OpenLayers.Util.getResolutionFromScale(props.maxScale,
+                                                       this.units);
+        } else if(props.minResolution == "auto" && this.minExtent != null) {
+            var viewSize = this.map.getSize();
+            var wRes = this.minExtent.getWidth() / viewSize.w;
+            var hRes = this.minExtent.getHeight()/ viewSize.h;
+            minResolution = Math.max(wRes, hRes);
+        }
+
+        // determine numZoomLevels
+        var maxZoomLevel = props.maxZoomLevel;
+        var numZoomLevels = props.numZoomLevels;
+        if(typeof minResolution === "number" &&
+           typeof maxResolution === "number" && numZoomLevels === undefined) {
+            var ratio = maxResolution / minResolution;
+            numZoomLevels = Math.floor(Math.log(ratio) / Math.log(2)) + 1;
+        } else if(numZoomLevels === undefined && maxZoomLevel != null) {
+            numZoomLevels = maxZoomLevel + 1;
+        }
+
+        // are we able to calculate resolutions?
+        if(typeof numZoomLevels !== "number" || numZoomLevels <= 0 ||
+           (typeof maxResolution !== "number" &&
+                typeof minResolution !== "number")) {
+            return;
+        }
+
+        // now we have numZoomLevels and at least one of maxResolution
+        // or minResolution, we can populate the resolutions array
+
+        var resolutions = new Array(numZoomLevels);
+        var base = 2;
+        if(typeof minResolution == "number" &&
+           typeof maxResolution == "number") {
+            // if maxResolution and minResolution are set, we calculate
+            // the base for exponential scaling that starts at
+            // maxResolution and ends at minResolution in numZoomLevels
+            // steps.
+            base = Math.pow(
+                    (maxResolution / minResolution),
+                (1 / (numZoomLevels - 1))
+            );
+        }
+
+        var i;
+        if(typeof maxResolution === "number") {
+            for(i=0; i<numZoomLevels; i++) {
+                resolutions[i] = maxResolution / Math.pow(base, i);
+            }
+        } else {
+            for(i=0; i<numZoomLevels; i++) {
+                resolutions[numZoomLevels - 1 - i] =
+                    minResolution * Math.pow(base, i);
+            }
+        }
+
+        return resolutions;
+    },
+
+    /**
+     * APIMethod: getResolution
+     * 
+     * Returns:
+     * {Float} The currently selected resolution of the map, taken from the
+     *     resolutions array, indexed by current zoom level.
+     */
+    getResolution: function() {
+        var zoom = this.map.getZoom();
+        return this.getResolutionForZoom(zoom);
+    },
+
+    /** 
+     * APIMethod: getExtent
+     * 
+     * Returns:
+     * {<OpenLayers.Bounds>} A Bounds object which represents the lon/lat 
+     *     bounds of the current viewPort.
+     */
+    getExtent: function() {
+        // just use stock map calculateBounds function -- passing no arguments
+        //  means it will user map's current center & resolution
+        //
+        return this.map.calculateBounds();
+    },
+
+    /**
+     * APIMethod: getZoomForExtent
+     * 
+     * Parameters:
+     * bounds - {<OpenLayers.Bounds>}
+     * closest - {Boolean} Find the zoom level that most closely fits the 
+     *     specified bounds. Note that this may result in a zoom that does 
+     *     not exactly contain the entire extent.
+     *     Default is false.
+     *
+     * Returns:
+     * {Integer} The index of the zoomLevel (entry in the resolutions array) 
+     *     for the passed-in extent. We do this by calculating the ideal 
+     *     resolution for the given extent (based on the map size) and then 
+     *     calling getZoomForResolution(), passing along the 'closest'
+     *     parameter.
+     */
+    getZoomForExtent: function(extent, closest) {
+        var viewSize = this.map.getSize();
+        var idealResolution = Math.max( extent.getWidth()  / viewSize.w,
+                                        extent.getHeight() / viewSize.h );
+
+        return this.getZoomForResolution(idealResolution, closest);
+    },
+    
+    /** 
+     * Method: getDataExtent
+     * Calculates the max extent which includes all of the data for the layer.
+     *     This function is to be implemented by subclasses.
+     * 
+     * Returns:
+     * {<OpenLayers.Bounds>}
+     */
+    getDataExtent: function () {
+        //to be implemented by subclasses
+    },
+
+    /**
+     * APIMethod: getResolutionForZoom
+     * 
+     * Parameter:
+     * zoom - {Float}
+     * 
+     * Returns:
+     * {Float} A suitable resolution for the specified zoom.
+     */
+    getResolutionForZoom: function(zoom) {
+        zoom = Math.max(0, Math.min(zoom, this.resolutions.length - 1));
+        var resolution;
+        if(this.map.fractionalZoom) {
+            var low = Math.floor(zoom);
+            var high = Math.ceil(zoom);
+            resolution = this.resolutions[low] -
+                ((zoom-low) * (this.resolutions[low]-this.resolutions[high]));
+        } else {
+            resolution = this.resolutions[Math.round(zoom)];
+        }
+        return resolution;
+    },
+
+    /**
+     * APIMethod: getZoomForResolution
+     * 
+     * Parameters:
+     * resolution - {Float}
+     * closest - {Boolean} Find the zoom level that corresponds to the absolute 
+     *     closest resolution, which may result in a zoom whose corresponding
+     *     resolution is actually smaller than we would have desired (if this
+     *     is being called from a getZoomForExtent() call, then this means that
+     *     the returned zoom index might not actually contain the entire 
+     *     extent specified... but it'll be close).
+     *     Default is false.
+     * 
+     * Returns:
+     * {Integer} The index of the zoomLevel (entry in the resolutions array) 
+     *     that corresponds to the best fit resolution given the passed in 
+     *     value and the 'closest' specification.
+     */
+    getZoomForResolution: function(resolution, closest) {
+        var zoom;
+        if(this.map.fractionalZoom) {
+            var lowZoom = 0;
+            var highZoom = this.resolutions.length - 1;
+            var highRes = this.resolutions[lowZoom];
+            var lowRes = this.resolutions[highZoom];
+            var res;
+            for(var i=0, len=this.resolutions.length; i<len; ++i) {
+                res = this.resolutions[i];
+                if(res >= resolution) {
+                    highRes = res;
+                    lowZoom = i;
+                }
+                if(res <= resolution) {
+                    lowRes = res;
+                    highZoom = i;
+                    break;
+                }
+            }
+            var dRes = highRes - lowRes;
+            if(dRes > 0) {
+                zoom = lowZoom + ((highRes - resolution) / dRes);
+            } else {
+                zoom = lowZoom;
+            }
+        } else {
+            var diff;
+            var minDiff = Number.POSITIVE_INFINITY;
+            for(var i=0, len=this.resolutions.length; i<len; i++) {            
+                if (closest) {
+                    diff = Math.abs(this.resolutions[i] - resolution);
+                    if (diff > minDiff) {
+                        break;
+                    }
+                    minDiff = diff;
+                } else {
+                    if (this.resolutions[i] < resolution) {
+                        break;
+                    }
+                }
+            }
+            zoom = Math.max(0, i-1);
+        }
+        return zoom;
+    },
+    
+    /**
+     * APIMethod: getLonLatFromViewPortPx
+     * 
+     * Parameters:
+     * viewPortPx - {<OpenLayers.Pixel>}
+     *
+     * Returns:
+     * {<OpenLayers.LonLat>} An OpenLayers.LonLat which is the passed-in 
+     *     view port <OpenLayers.Pixel>, translated into lon/lat by the layer.
+     */
+    getLonLatFromViewPortPx: function (viewPortPx) {
+        var lonlat = null;
+        if (viewPortPx != null) {
+            var size = this.map.getSize();
+            var center = this.map.getCenter();
+            if (center) {
+                var res  = this.map.getResolution();
+        
+                var delta_x = viewPortPx.x - (size.w / 2);
+                var delta_y = viewPortPx.y - (size.h / 2);
+            
+                lonlat = new OpenLayers.LonLat(center.lon + delta_x * res ,
+                                             center.lat - delta_y * res); 
+
+                if (this.wrapDateLine) {
+                    lonlat = lonlat.wrapDateLine(this.maxExtent);
+                }
+            } // else { DEBUG STATEMENT }
+        }
+        return lonlat;
+    },
+
+    /**
+     * APIMethod: getViewPortPxFromLonLat
+     * Returns a pixel location given a map location.  This method will return
+     *     fractional pixel values.
+     * 
+     * Parameters:
+     * lonlat - {<OpenLayers.LonLat>}
+     *
+     * Returns: 
+     * {<OpenLayers.Pixel>} An <OpenLayers.Pixel> which is the passed-in 
+     *     <OpenLayers.LonLat>,translated into view port pixels.
+     */
+    getViewPortPxFromLonLat: function (lonlat) {
+        var px = null; 
+        if (lonlat != null) {
+            var resolution = this.map.getResolution();
+            var extent = this.map.getExtent();
+            px = new OpenLayers.Pixel(
+                (1/resolution * (lonlat.lon - extent.left)),
+                (1/resolution * (extent.top - lonlat.lat))
+            );    
+        }
+        return px;
+    },
+    
+    /**
+     * APIMethod: setOpacity
+     * Sets the opacity for the entire layer (all images)
+     * 
+     * Parameter:
+     * opacity - {Float}
+     */
+    setOpacity: function(opacity) {
+        if (opacity != this.opacity) {
+            this.opacity = opacity;
+            for(var i=0, len=this.div.childNodes.length; i<len; ++i) {
+                var element = this.div.childNodes[i].firstChild;
+                OpenLayers.Util.modifyDOMElement(element, null, null, null, 
+                                                 null, null, null, opacity);
+            }
+            if (this.map != null) {
+                this.map.events.triggerEvent("changelayer", {
+                    layer: this,
+                    property: "opacity"
+                });
+            }
+        }
+    },
+
+    /**
+     * Method: getZIndex
+     * 
+     * Returns: 
+     * {Integer} the z-index of this layer
+     */    
+    getZIndex: function () {
+        return this.div.style.zIndex;
+    },
+
+    /**
+     * Method: setZIndex
+     * 
+     * Parameters: 
+     * zIndex - {Integer}
+     */    
+    setZIndex: function (zIndex) {
+        this.div.style.zIndex = zIndex;
+    },
+
+    /**
+     * Method: adjustBounds
+     * This function will take a bounds, and if wrapDateLine option is set
+     *     on the layer, it will return a bounds which is wrapped around the 
+     *     world. We do not wrap for bounds which *cross* the 
+     *     maxExtent.left/right, only bounds which are entirely to the left 
+     *     or entirely to the right.
+     * 
+     * Parameters:
+     * bounds - {<OpenLayers.Bounds>}
+     */
+    adjustBounds: function (bounds) {
+
+        if (this.gutter) {
+            // Adjust the extent of a bounds in map units by the 
+            // layer's gutter in pixels.
+            var mapGutter = this.gutter * this.map.getResolution();
+            bounds = new OpenLayers.Bounds(bounds.left - mapGutter,
+                                           bounds.bottom - mapGutter,
+                                           bounds.right + mapGutter,
+                                           bounds.top + mapGutter);
+        }
+
+        if (this.wrapDateLine) {
+            // wrap around the date line, within the limits of rounding error
+            var wrappingOptions = { 
+                'rightTolerance':this.getResolution()
+            };    
+            bounds = bounds.wrapDateLine(this.maxExtent, wrappingOptions);
+                              
+        }
+        return bounds;
+    },
+
+    CLASS_NAME: "OpenLayers.Layer"
+});
+