OpenLayers.Layer

{String}

{String}

{DOMElement}

{Float} The layer’s opacity.  Float number between 0.0 and 1.0.  Default is 1.

{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.

{OpenLayers.Events}

Register a listener for a particular event with the following syntax

layer.events.register(type, obj, listener);

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

Supported map event types

{OpenLayers.Map} This variable is set when the layer is added to the map, via the accessor function setMap().

{Boolean} Whether or not the layer is a base layer.  This should be set individually by all subclasses.  Default is false

{Boolean} Display the layer’s name in the layer switcher.  Default is true.

{Boolean} The layer should be displayed in the map.  Default is true.

{String} Attribution string, displayed when an OpenLayers.Control.Attribution has been added to the map.

{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.

{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.

{OpenLayers.Projection} or {String} Specifies the projection of the layer.  Can be set in the layer options.  If not specified in the layer options, it is set to the default projection specified in the map, when the layer is added to the map.  Projection along with default maxExtent and resolutions are set automatically with commercial baselayers in EPSG:3857, such as Google, Bing and OpenStreetMap, and do not need to be specified.  Otherwise, if specifying projection, also set maxExtent, maxResolution or resolutions as appropriate.  When using vector layers with strategies, layer projection should be set to the projection of the source data if that is different from the map default.

Can be either a string or an OpenLayers.Projection object; if a string is passed, will be converted to an object when the layer is added to the map.

{String} The layer map units.  Defaults to null.  Possible values are ‘degrees’ (or ‘dd’), ‘m’, ‘ft’, ‘km’, ‘mi’, ‘inches’.  Normally taken from the projection.  Only required if both map and layers do not define a projection, or if they define a projection which does not define units.

{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.

{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.).

{<OpenLayers.Bounds>|Array} If provided as an array, the array should consist of four values (left, bottom, right, top).  The maximum extent for the layer.  Defaults to null.

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.

{<OpenLayers.Bounds>|Array} If provided as an array, the array should consist of four values (left, bottom, right, top).  The minimum extent for the layer.  Defaults to null.

{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 the default OpenLayers.Map.tileSize and displaying the whole world.

{Float}

{Integer}

{Float}

{Float}

{Boolean} Request map tiles that are completely outside of the max extent for this layer.  Defaults to false.

{Boolean} Wraps the world at the international dateline, so the map can be panned infinitely in longitudinal direction.  Only use this on the base layer, and only if the layer’s maxExtent equals the world bounds.  #487 for more info.