OpenLayers.Map

Instances of OpenLayers.Map are interactive maps embedded in a web page.  Create a new map with the OpenLayers.Map constructor.

On their own maps do not provide much functionality.  To extend a map it’s necessary to add controls (OpenLayers.Control) and layers (OpenLayers.Layer) to the map.

Summary
OpenLayers.MapInstances of OpenLayers.Map are interactive maps embedded in a web page.
Constants
Z_INDEX_BASE{Object} Base z-indexes for different classes of thing
Properties
events{OpenLayers.Events}
events{OpenLayers.Events} An events object that handles all events on the map
allOverlays{Boolean} Allow the map to function with “overlays” only.
div{DOMElement|String} The element that contains the map (or an id for that element).
layers{Array(OpenLayers.Layer)} Ordered list of layers in the map
controls{Array(OpenLayers.Control)} List of controls associated with the map.
baseLayer{OpenLayers.Layer} The currently selected base layer.
options{Object} The options object passed to the class constructor.
tileSize{OpenLayers.Size} Set in the map options to override the default tile size for this map.
projection{String} Set in the map options to specify the default projection for layers added to this map.
units{String} The map units.
resolutions{Array(Float)} A list of map resolutions (map units per pixel) in descending order.
maxResolution{Float} Required if you are not displaying the whole world on a tile with the size specified in tileSize.
minResolution{Float}
maxScale{Float}
minScale{Float}
maxExtent{<OpenLayers.Bounds>|Array} If provided as an array, the array should consist of four values (left, bottom, right, top).
minExtent{<OpenLayers.Bounds>|Array} If provided as an array, the array should consist of four values (left, bottom, right, top).
restrictedExtent{<OpenLayers.Bounds>|Array} If provided as an array, the array should consist of four values (left, bottom, right, top).
numZoomLevels{Integer} Number of zoom levels for the map.
theme{String} Relative path to a CSS file from which to load theme styles.
displayProjection{OpenLayers.Projection} Requires proj4js support for projections other than EPSG:4326 or EPSG:900913/EPSG:3857.
tileManager{<OpenLayers.TileManager>|Object} By default, and if the build contains TileManager.js, the map will use the TileManager to queue image requests and to cache tile image elements.
fallThrough{Boolean} Should OpenLayers allow events on the map to fall through to other elements on the page, or should it swallow them? 
autoUpdateSize{Boolean} Should OpenLayers automatically update the size of the map when the resize event is fired.
eventListeners{Object} If set as an option at construction, the eventListeners object will be registered with OpenLayers.Events.on.
panMethod{Function} The Easing function to be used for tweening.
zoomMethod{Function} The Easing function to be used for tweening.
Constructor
OpenLayers.MapConstructor for a new OpenLayers.Map instance.
Functions
getViewportGet the DOMElement representing the view port.
renderRender the map to a specified container.
destroyDestroy this map.
setOptionsChange the map options
getTileSizeGet the tile size for the map
getByGet a list of objects given a property and a match item.
getLayersByGet a list of layers with properties matching the given criteria.
getLayersByNameGet a list of layers with names matching the given name.
getLayersByClassGet a list of layers of a given class (CLASS_NAME).
getControlsByGet a list of controls with properties matching the given criteria.
getControlsByClassGet a list of controls of a given class (CLASS_NAME).
getLayerGet a layer based on its id
addLayer
addLayers
removeLayerRemoves 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.
getNumLayers{Int} The number of layers attached to the map.
getLayerIndex
setLayerIndexMove the given layer to the specified (zero-based) index in the layer list, changing its z-index in the map display.
raiseLayerChange the index of the given layer by delta.
setBaseLayerAllows user to specify one of the currently-loaded layers as the Map’s new base layer.
addControlAdd the passed over control to the map.
addControlsAdd all of the passed over controls to the map.
getControl
removeControlRemove a control from the map.
addPopup
removePopup
getSize{OpenLayers.Size} An OpenLayers.Size object that represents the size, in pixels, of the div into which OpenLayers has been loaded.
updateSizeThis 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)
getCenter{OpenLayers.LonLat}
getZoom{Integer}
panAllows user to pan by a value of screen pixels
panToAllows user to pan to a new lonlat.
setCenterSet the map center (and optionally, the zoom level).
getMinZoomReturns the minimum zoom level for the current map view.
getProjectionThis method returns a string representing the projection.
getProjectionObjectReturns the projection obect from the baselayer.
getMaxResolution{String} The Map’s Maximum Resolution
getMaxExtent
getNumZoomLevels{Integer} The total number of zoom levels that can be displayed by the current baseLayer.
getExtent{OpenLayers.Bounds} A Bounds object which represents the lon/lat bounds of the current viewPort.
getResolution{Float} The current resolution of the map.
getUnits{Float} The current units of the map.
getScale{Float} The current scale denominator of the map.
getZoomForExtent
getResolutionForZoom
getZoomForResolution
zoomToZoom to a specific zoom level.
zoomIn
zoomOut
zoomToExtentZoom to the passed in bounds, recenter
zoomToMaxExtentZoom to the full extent and recenter.
zoomToScaleZoom to a specified scale
getViewPortPxFromLonLat
getLonLatFromPixel
getPixelFromLonLatReturns a pixel location given a map location.
getViewPortPxFromLayerPx
getLayerPxFromViewPortPx
getLayerPxFromLonLat
Constants
TILE_WIDTH{Integer} 256 Default tile width (unless otherwise specified)
TILE_HEIGHT{Integer} 256 Default tile height (unless otherwise specified)

Constants

Z_INDEX_BASE

{Object} Base z-indexes for different classes of thing

Properties

events

{OpenLayers.Events}

Register a listener for a particular event with the following syntax

map.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

object{Object} A reference to map.events.object.
element{DOMElement} A reference to map.events.element.

Browser events have the following additional properties

xy{OpenLayers.Pixel} The pixel location of the event (relative to the the map viewport).

Supported map event types

preaddlayertriggered before a layer has been added.  The event object will include a layer property that references the layer to be added.  When a listener returns “false” the adding will be aborted.
addlayertriggered after a layer has been added.  The event object will include a layer property that references the added layer.
preremovelayertriggered before a layer has been removed.  The event object will include a layer property that references the layer to be removed.  When a listener returns “false” the removal will be aborted.
removelayertriggered after a layer has been removed.  The event object will include a layer property that references the removed layer.
changelayertriggered after a layer name change, order change, opacity change, params change, visibility change (actual visibility, not the layer’s visibility property) or attribution change (due to extent change).  Listeners will receive an event object with layer and property properties.  The layer property will be a reference to the changed layer.  The property property will be a key to the changed property (name, order, opacity, params, visibility or attribution).
movestarttriggered after the start of a drag, pan, or zoom.  The event object may include a zoomChanged property that tells whether the zoom has changed.
movetriggered after each drag, pan, or zoom
moveendtriggered after a drag, pan, or zoom completes
zoomstarttriggered when a zoom starts.  Listeners receive an object with center and zoom properties, for the target center and zoom level.
zoomendtriggered after a zoom completes
mouseovertriggered after mouseover the map
mouseouttriggered after mouseout the map
mousemovetriggered after mousemove the map
changebaselayertriggered after the base layer changes
updatesizetriggered after the updateSize method was executed

events

{OpenLayers.Events} An events object that handles all events on the map

allOverlays

{Boolean} Allow the map to function with “overlays” only.  Defaults to false.  If true, the lowest layer in the draw order will act as the base layer.  In addition, if set to true, all layers will have isBaseLayer set to false when they are added to the map.

Note

If you set map.allOverlays to true, then you cannot use map.setBaseLayer or layer.setIsBaseLayer.  With allOverlays true, the lowest layer in the draw layer is the base layer.  So, to change the base layer, use setLayerIndex or raiseLayer to set the layer index to 0.

div

{DOMElement|String} The element that contains the map (or an id for that element).  If the OpenLayers.Map constructor is called with two arguments, this should be provided as the first argument.  Alternatively, the map constructor can be called with the options object as the only argument.  In this case (one argument), a div property may or may not be provided.  If the div property is not provided, the map can be rendered to a container later using the render method.

Note

If you are calling render after map construction, do not use maxResolution auto.  Instead, divide your maxExtent by your maximum expected dimension.

layers

{Array(OpenLayers.Layer)} Ordered list of layers in the map

controls

{Array(OpenLayers.Control)} List of controls associated with the map.

If not provided in the map options at construction, the map will by default be given the following controls if present in the build:

baseLayer

{OpenLayers.Layer} The currently selected base layer.  This determines min/max zoom level, projection, etc.

options

{Object} The options object passed to the class constructor.  Read-only.

tileSize

{OpenLayers.Size} Set in the map options to override the default tile size for this map.

projection

{String} Set in the map options to specify the default projection for layers added to this map.  When using a projection other than EPSG:4326 (CRS:84, Geographic) or EPSG:3857 (EPSG:900913, Web Mercator), also set maxExtent, maxResolution or resolutions.  Default is “EPSG:4326”.  Note that the projection of the map is usually determined by that of the current baseLayer (see baseLayer and getProjectionObject).

units

{String} The map units.  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

resolutions

{Array(Float)} 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.).

maxResolution

{Float} Required if you are not displaying the whole world on a tile with the size specified in tileSize.

minResolution

{Float}

maxScale

{Float}

minScale

{Float}

maxExtent

{<OpenLayers.Bounds>|Array} If provided as an array, the array should consist of four values (left, bottom, right, top).  The maximum extent for the map.  Default depends on projection; if this is one of those defined in OpenLayers.Projection.defaults (EPSG:4326 or web mercator), maxExtent will be set to the value defined there; else, defaults to null.  To restrict user panning and zooming of the map, use restrictedExtent instead.  The value for maxExtent will change calculations for tile URLs.

minExtent

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

restrictedExtent

{<OpenLayers.Bounds>|Array} If provided as an array, the array should consist of four values (left, bottom, right, top).  Limit map navigation to this extent where possible.  If a non-null restrictedExtent is set, panning will be restricted to the given bounds.  In addition, zooming to a resolution that displays more than the restricted extent will center the map on the restricted extent.  If you wish to limit the zoom level or resolution, use maxResolution.

numZoomLevels

{Integer} Number of zoom levels for the map.  Defaults to 16.  Set a different value in the map options if needed.

theme

{String} Relative path to a CSS file from which to load theme styles.  Specify null in the map options (e.g.  {theme: null}) if you want to get cascading style declarations - by putting links to stylesheets or style declarations directly in your page.

displayProjection

{OpenLayers.Projection} Requires proj4js support for projections other than EPSG:4326 or EPSG:900913/EPSG:3857.  Projection used by several controls to display data to user.  If this property is set, it will be set on any control which has a null displayProjection property at the time the control is added to the map.

tileManager

{<OpenLayers.TileManager>|Object} By default, and if the build contains TileManager.js, the map will use the TileManager to queue image requests and to cache tile image elements.  To create a map without a TileManager configure the map with tileManager: null.  To create a TileManager with non-default options, supply the options instead or alternatively supply an instance of {OpenLayers.TileManager}.

fallThrough

{Boolean} Should OpenLayers allow events on the map to fall through to other elements on the page, or should it swallow them?  (#457) Default is to swallow.

autoUpdateSize

{Boolean} Should OpenLayers automatically update the size of the map when the resize event is fired.  Default is true.

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.

panMethod

{Function} The Easing function to be used for tweening.  Default is OpenLayers.Easing.Expo.easeOut.  Setting this to ‘null’ turns off animated panning.

zoomMethod

{Function} The Easing function to be used for tweening.  Default is OpenLayers.Easing.Quad.easeOut.  Setting this to ‘null’ turns off animated zooming.

Constructor

OpenLayers.Map

Constructor for a new OpenLayers.Map instance.  There are two possible ways to call the map constructor.  See the examples below.

Parameters

div{DOMElement|String} The element or id of an element in your page that will contain the map.  May be omitted if the div option is provided or if you intend to call the render method later.
options{Object} Optional object with properties to tag onto the map.

Valid options (in addition to the listed API properties)

center{<OpenLayers.LonLat>|Array} The default initial center of the map.  If provided as array, the first value is the x coordinate, and the 2nd value is the y coordinate.  Only specify if layers is provided.  Note that if an ArgParser/Permalink control is present, and the querystring contains coordinates, center will be set by that, and this option will be ignored.
zoom{Number} The initial zoom level for the map.  Only specify if layers is provided.  Note that if an ArgParser/Permalink control is present, and the querystring contains a zoom level, zoom will be set by that, and this option will be ignored.

Examples

// create a map with default options in an element with the id "map1"
var map = new OpenLayers.Map("map1");

// create a map with non-default options in an element with id "map2"
var options = {
    projection: "EPSG:3857",
    maxExtent: new OpenLayers.Bounds(-200000, -200000, 200000, 200000),
    center: new OpenLayers.LonLat(-12356463.476333, 5621521.4854095)
};
var map = new OpenLayers.Map("map2", options);

// map with non-default options - same as above but with a single argument,
// a restricted extent, and using arrays for bounds and center
var map = new OpenLayers.Map({
    div: "map_id",
    projection: "EPSG:3857",
    maxExtent: [-18924313.432222, -15538711.094146, 18924313.432222, 15538711.094146],
    restrictedExtent: [-13358338.893333, -9608371.5085962, 13358338.893333, 9608371.5085962],
    center: [-12356463.476333, 5621521.4854095]
});

// create a map without a reference to a container - call render later
var map = new OpenLayers.Map({
    projection: "EPSG:3857",
    maxExtent: new OpenLayers.Bounds(-200000, -200000, 200000, 200000)
});

Functions

getViewport

getViewport: function()

Get the DOMElement representing the view port.

Returns

{DOMElement}

render

render: function(div)

Render the map to a specified container.

Parameters

div{String|DOMElement} The container that the map should be rendered to.  If different than the current container, the map viewport will be moved from the current to the new container.

destroy

destroy:function()

Destroy this map.  Note that if you are using an application which removes a container of the map from the DOM, you need to ensure that you destroy the map before this happens; otherwise, the page unload handler will fail because the DOM elements that map.destroy() wants to clean up will be gone. 

setOptions

setOptions: function(options)

Change the map options

Parameters

options{Object} Hashtable of options to tag to the map

getTileSize

getTileSize: function()

Get the tile size for the map

Returns

{OpenLayers.Size}

getBy

getBy: function(array,
property,
match)

Get a list of objects given a property and a match item.

Parameters

array{String} A property on the map whose value is an array.
property{String} A property on each item of the given array.
match{String | Object} A string to match.  Can also be a regular expression literal or object.  In addition, it can be any object with a method named test.  For reqular expressions or other, if match.test(map[array][i][property]) evaluates to true, the item will be included in the array returned.  If no items are found, an empty array is returned.

Returns

{Array} An array of items where the given property matches the given criteria.

getLayersBy

getLayersBy: function(property,
match)

Get a list of layers with properties matching the given criteria.

Parameters

property{String} A layer property to be matched.
match{String | Object} A string to match.  Can also be a regular expression literal or object.  In addition, it can be any object with a method named test.  For reqular expressions or other, if match.test(layer[property]) evaluates to true, the layer will be included in the array returned.  If no layers are found, an empty array is returned.

Returns

{Array(OpenLayers.Layer)} A list of layers matching the given criteria.  An empty array is returned if no matches are found.

getLayersByName

getLayersByName: function(match)

Get a list of layers with names matching the given name.

Parameters

match{String | Object} A layer name.  The name can also be a regular expression literal or object.  In addition, it can be any object with a method named test.  For reqular expressions or other, if name.test(layer.name) evaluates to true, the layer will be included in the list of layers returned.  If no layers are found, an empty array is returned.

Returns

{Array(OpenLayers.Layer)} A list of layers matching the given name.  An empty array is returned if no matches are found.

getLayersByClass

getLayersByClass: function(match)

Get a list of layers of a given class (CLASS_NAME).

Parameters

match{String | Object} A layer class name.  The match can also be a regular expression literal or object.  In addition, it can be any object with a method named test.  For reqular expressions or other, if type.test(layer.CLASS_NAME) evaluates to true, the layer will be included in the list of layers returned.  If no layers are found, an empty array is returned.

Returns

{Array(OpenLayers.Layer)} A list of layers matching the given class.  An empty array is returned if no matches are found.

getControlsBy

getControlsBy: function(property,
match)

Get a list of controls with properties matching the given criteria.

Parameters

property{String} A control property to be matched.
match{String | Object} A string to match.  Can also be a regular expression literal or object.  In addition, it can be any object with a method named test.  For reqular expressions or other, if match.test(layer[property]) evaluates to true, the layer will be included in the array returned.  If no layers are found, an empty array is returned.

Returns

{Array(OpenLayers.Control)} A list of controls matching the given criteria.  An empty array is returned if no matches are found.

getControlsByClass

getControlsByClass: function(match)

Get a list of controls of a given class (CLASS_NAME).

Parameters

match{String | Object} A control class name.  The match can also be a regular expression literal or object.  In addition, it can be any object with a method named test.  For reqular expressions or other, if type.test(control.CLASS_NAME) evaluates to true, the control will be included in the list of controls returned.  If no controls are found, an empty array is returned.

Returns

{Array(OpenLayers.Control)} A list of controls matching the given class.  An empty array is returned if no matches are found.

getLayer

getLayer: function(id)

Get a layer based on its id

Parameters

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.

addLayer

addLayer: function (layer)

Parameters

layer{OpenLayers.Layer}

Returns

{Boolean} True if the layer has been added to the map.

addLayers

addLayers: function (layers)

Parameters

layers{Array(OpenLayers.Layer)}

removeLayer

removeLayer: function(layer,
setNewBaseLayer)

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

getNumLayers

getNumLayers: function ()

Returns

{Int} The number of layers attached to the map.

getLayerIndex

getLayerIndex: function (layer)

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.

setLayerIndex

setLayerIndex: function (layer,
idx)

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}

raiseLayer

raiseLayer: function (layer,
delta)

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.

Parameters

layer{OpenLayers.Layer}
delta{int}

setBaseLayer

setBaseLayer: function(newBaseLayer)

Allows user to specify one of the currently-loaded layers as the Map’s new base layer.

Parameters

newBaseLayer{OpenLayers.Layer}

addControl

addControl: function (control,
px)

Add the passed over control to the map.  Optionally position the control at the given pixel.

Parameters

control{OpenLayers.Control}
px{OpenLayers.Pixel}

addControls

addControls: function (controls,
pixels)

Add all of the passed over controls to the map.  You can pass over an optional second array with pixel-objects to position the controls.  The indices of the two arrays should match and you can add null as pixel for those controls you want to be autopositioned.

Parameters

controls{Array(OpenLayers.Control)}
pixels{Array(OpenLayers.Pixel)}

getControl

getControl: function (id)

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.

removeControl

removeControl: function (control)

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.

addPopup

addPopup: function(popup,
exclusive)

Parameters

popup{OpenLayers.Popup}
exclusive{Boolean} If true, closes all other popups first

removePopup

removePopup: function(popup)

Parameters

popup{OpenLayers.Popup}

getSize

getSize: function ()

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.

updateSize

updateSize: function()

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)

getCenter

getCenter: function ()

Returns

{OpenLayers.LonLat}

getZoom

getZoom: function ()

Returns

{Integer}

pan

pan: function(dx,
dy,
options)

Allows user to pan by a value of screen pixels

Parameters

dx{Integer}
dy{Integer}
options{Object} Options to configure panning:
  • animate {Boolean} Use panTo instead of setCenter.  Default is true.
  • dragging {Boolean} Call setCenter with dragging true.  Default is false.

panTo

panTo: function(lonlat)

Allows user to pan to a new lonlat.  If the new lonlat is in the current extent the map will slide smoothly

Parameters

lonlat{OpenLayers.LonLat}

setCenter

setCenter: function(lonlat,
zoom,
dragging,
forceZoomChange)

Set the map center (and optionally, the zoom level).

Parameters

lonlat{<OpenLayers.LonLat>|Array} The new center location.  If provided as array, the first value is the x coordinate, and the 2nd value is the y coordinate.
zoom{Integer} Optional zoom level.
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

getMinZoom

getMinZoom: function()

Returns the minimum zoom level for the current map view.  If the base layer is configured with <wrapDateLine> set to true, this will be the first zoom level that shows no more than one world width in the current map viewport.  Components that rely on this value (e.g. zoom sliders) should also listen to the map’s “updatesize” event and call this method in the “updatesize” listener.

Returns

{Number} Minimum zoom level that shows a map not wider than its baseLayer’s maxExtent.  This is an Integer value, unless the map is configured with <fractionalZoom> set to true.

getProjection

getProjection: function()

This method returns a string representing the projection.  In the case of projection support, this will be the srsCode which is loaded -- otherwise it will simply be the string value that was passed to the projection at startup.

FIXME: In 3.0, we will remove getProjectionObject, and instead return a Projection object from this function.

Returns

{String} The Projection string from the base layer or null.

getProjectionObject

getProjectionObject: function()

Returns the projection obect from the baselayer.

Returns

{OpenLayers.Projection} The Projection of the base layer.

getMaxResolution

getMaxResolution: function()

Returns

{String} The Map’s Maximum Resolution

getMaxExtent

getMaxExtent: function (options)

Parameters

options{Object}

Allowed Options

restricted{Boolean} If true, returns restricted extent (if it is available.)

Returns

{OpenLayers.Bounds} The maxExtent property as set on the current baselayer, unless the ‘restricted’ option is set, in which case the ‘restrictedExtent’ option from the map is returned (if it is set).

getNumZoomLevels

getNumZoomLevels: function()

Returns

{Integer} The total number of zoom levels that can be displayed by the current baseLayer.

getExtent

getExtent: function ()

Returns

{OpenLayers.Bounds} A Bounds object which represents the lon/lat bounds of the current viewPort.  If no baselayer is set, returns null.

getResolution

getResolution: function ()

Returns

{Float} The current resolution of the map.  If no baselayer is set, returns null.

getUnits

getUnits: function ()

Returns

{Float} The current units of the map.  If no baselayer is set, returns null.

getScale

getScale: function ()

Returns

{Float} The current scale denominator of the map.  If no baselayer is set, returns null.

getZoomForExtent

getZoomForExtent: function (bounds,
closest)

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} A suitable zoom level for the specified bounds.  If no baselayer is set, returns null.

getResolutionForZoom

getResolutionForZoom: function(zoom)

Parameters

zoom{Float}

Returns

{Float} A suitable resolution for the specified zoom.  If no baselayer is set, returns null.

getZoomForResolution

getZoomForResolution: function(resolution,
closest)

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} A suitable zoom level for the specified resolution.  If no baselayer is set, returns null.

zoomTo

zoomTo: function(zoom,
xy)

Zoom to a specific zoom level.  Zooming will be animated unless the map is configured with {zoomMethod: null}.  To zoom without animation, use setCenter without a lonlat argument.

Parameters

zoom{Integer}

zoomIn

zoomIn: function()

zoomOut

zoomOut: function()

zoomToExtent

zoomToExtent: function(bounds,
closest)

Zoom to the passed in bounds, recenter

Parameters

bounds{<OpenLayers.Bounds>|Array} If provided as an array, the array should consist of four values (left, bottom, right, top).
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.

zoomToMaxExtent

zoomToMaxExtent: function(options)

Zoom to the full extent and recenter.

Parameters

options{Object}

Allowed Options

restricted{Boolean} True to zoom to restricted extent if it is set.  Defaults to true.

zoomToScale

zoomToScale: function(scale,
closest)

Zoom to a specified scale

Parameters

scale{float}
closest{Boolean} Find the zoom level that most closely fits the specified scale.  Note that this may result in a zoom that does not exactly contain the entire extent.  Default is false.

getViewPortPxFromLonLat

getViewPortPxFromLonLat: function (lonlat)

Parameters

lonlat{OpenLayers.LonLat}

Returns

{OpenLayers.Pixel} An OpenLayers.Pixel which is the passed-in OpenLayers.LonLat, translated into view port pixels by the current base layer.

getLonLatFromPixel

getLonLatFromPixel: function (px)

Parameters

px{<OpenLayers.Pixel>|Object} An OpenLayers.Pixel or an object with a ‘x’ and ‘y’ properties.

Returns

{OpenLayers.LonLat} An OpenLayers.LonLat corresponding to the given OpenLayers.Pixel, translated into lon/lat by the current base layer

getPixelFromLonLat

getPixelFromLonLat: function (lonlat)

Returns a pixel location given a map location.  The map location is translated to an integer pixel location (in viewport pixel coordinates) by the current base layer.

Parameters

lonlat{OpenLayers.LonLat} A map location.

Returns

{OpenLayers.Pixel} An OpenLayers.Pixel corresponding to the OpenLayers.LonLat translated into view port pixels by the current base layer.

getViewPortPxFromLayerPx

getViewPortPxFromLayerPx:function(layerPx)

Parameters

layerPx{OpenLayers.Pixel}

Returns

{OpenLayers.Pixel} Layer Pixel translated into ViewPort Pixel coordinates

getLayerPxFromViewPortPx

getLayerPxFromViewPortPx:function(viewPortPx)

Parameters

viewPortPx{OpenLayers.Pixel}

Returns

{OpenLayers.Pixel} ViewPort Pixel translated into Layer Pixel coordinates

getLayerPxFromLonLat

getLayerPxFromLonLat: function (lonlat)

Parameters

lonlat{OpenLayers.LonLat} lonlat

Returns

{OpenLayers.Pixel} An OpenLayers.Pixel which is the passed-in OpenLayers.LonLat, translated into layer pixels by the current base layer

Constants

TILE_WIDTH

{Integer} 256 Default tile width (unless otherwise specified)

TILE_HEIGHT

{Integer} 256 Default tile height (unless otherwise specified)

Controls affect the display or behavior of the map.
Instances of this class represent a width/height pair
{OpenLayers.Size} Set in the map options to override the default tile size for this map.
Methods for coordinate transforms between coordinate systems.
on: function(object)
Convenience method for registering listeners with a common scope.
getViewport: function()
Get the DOMElement representing the view port.
render: function(div)
Render the map to a specified container.
destroy:function()
Destroy this map.
setOptions: function(options)
Change the map options
getTileSize: function()
Get the tile size for the map
getBy: function(array,
property,
match)
Get a list of objects given a property and a match item.
getLayersBy: function(property,
match)
Get a list of layers with properties matching the given criteria.
getLayersByName: function(match)
Get a list of layers with names matching the given name.
getLayersByClass: function(match)
Get a list of layers of a given class (CLASS_NAME).
getControlsBy: function(property,
match)
Get a list of controls with properties matching the given criteria.
getControlsByClass: function(match)
Get a list of controls of a given class (CLASS_NAME).
getLayer: function(id)
Get a layer based on its id
addLayer: function (layer)
addLayers: function (layers)
removeLayer: function(layer,
setNewBaseLayer)
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.
getNumLayers: function ()
{Int} The number of layers attached to the map.
getLayerIndex: function (layer)
setLayerIndex: function (layer,
idx)
Move the given layer to the specified (zero-based) index in the layer list, changing its z-index in the map display.
raiseLayer: function (layer,
delta)
Change the index of the given layer by delta.
setBaseLayer: function(newBaseLayer)
Allows user to specify one of the currently-loaded layers as the Map’s new base layer.
addControl: function (control,
px)
Add the passed over control to the map.
addControls: function (controls,
pixels)
Add all of the passed over controls to the map.
getControl: function (id)
removeControl: function (control)
Remove a control from the map.
addPopup: function(popup,
exclusive)
removePopup: function(popup)
getSize: function ()
{OpenLayers.Size} An OpenLayers.Size object that represents the size, in pixels, of the div into which OpenLayers has been loaded.
updateSize: function()
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)
getCenter: function ()
{OpenLayers.LonLat}
This class represents a longitude and latitude pair
getZoom: function ()
{Integer}
pan: function(dx,
dy,
options)
Allows user to pan by a value of screen pixels
panTo: function(lonlat)
Allows user to pan to a new lonlat.
setCenter: function(lonlat,
zoom,
dragging,
forceZoomChange)
Set the map center (and optionally, the zoom level).
getMinZoom: function()
Returns the minimum zoom level for the current map view.
getProjection: function()
This method returns a string representing the projection.
getProjectionObject: function()
Returns the projection obect from the baselayer.
getMaxResolution: function()
{String} The Map’s Maximum Resolution
getMaxExtent: function (options)
getNumZoomLevels: function()
{Integer} The total number of zoom levels that can be displayed by the current baseLayer.
getExtent: function ()
{OpenLayers.Bounds} A Bounds object which represents the lon/lat bounds of the current viewPort.
Instances of this class represent bounding boxes.
getResolution: function ()
{Float} The current resolution of the map.
getUnits: function ()
{Float} The current units of the map.
getScale: function ()
{Float} The current scale denominator of the map.
getZoomForExtent: function (bounds,
closest)
getResolutionForZoom: function(zoom)
getZoomForResolution: function(resolution,
closest)
zoomTo: function(zoom,
xy)
Zoom to a specific zoom level.
zoomIn: function()
zoomOut: function()
zoomToExtent: function(bounds,
closest)
Zoom to the passed in bounds, recenter
zoomToMaxExtent: function(options)
Zoom to the full extent and recenter.
zoomToScale: function(scale,
closest)
Zoom to a specified scale
getViewPortPxFromLonLat: function (lonlat)
getLonLatFromPixel: function (px)
getPixelFromLonLat: function (lonlat)
Returns a pixel location given a map location.
getViewPortPxFromLayerPx:function(layerPx)
getLayerPxFromViewPortPx:function(viewPortPx)
getLayerPxFromLonLat: function (lonlat)
Constructor for a new OpenLayers.Map instance.
This class represents a screen coordinate, in x and y coordinates
{Float} Required if you are not displaying the whole world on a tile with the size specified in tileSize.
{<OpenLayers.Bounds>|Array} If provided as an array, the array should consist of four values (left, bottom, right, top).
The navigation control handles map browsing with mouse events (dragging, double-clicking, and scrolling the wheel).
The navigation control handles map browsing with touch events (dragging, double-tapping, tap with two fingers, and pinch zoom).
The Zoom control is a pair of +/- links for zooming in and out.
The PanZoom is a visible control, composed of a OpenLayers.Control.PanPanel and a OpenLayers.Control.ZoomPanel.
The ArgParser control adds location bar query string parsing functionality to an OpenLayers Map.
The attribution control adds attribution from layers to the map display.
{OpenLayers.Layer} The currently selected base layer.
{<OpenLayers.Bounds>|Array} If provided as an array, the array should consist of four values (left, bottom, right, top).
Provides queueing of image requests and caching of image elements.
{DOMElement|String} The element that contains the map (or an id for that element).
{Array(OpenLayers.Layer)} Ordered list of layers in the map
A popup is a small div that can opened and closed on the map.