OpenLayers.Layer.Vector

Instances of OpenLayers.Layer.Vector are used to render vector data from a variety of sources. Create a new vector layer with the OpenLayers.Layer.Vector constructor.

Inherits from

OpenLayers.Layer

Summary

OpenLayers.Layer.Vector	Instances of OpenLayers.Layer.Vector are used to render vector data from a variety of sources.
Constants
EVENT_TYPES	{Array(String)} Supported application event types.
Properties
isBaseLayer	{Boolean} The layer is a base layer.
isFixed	{Boolean} Whether the layer remains in one place while dragging the map.
isVector	{Boolean} Whether the layer is a vector layer.
features	{Array(OpenLayers.Feature.Vector)}
selectedFeatures	{Array(OpenLayers.Feature.Vector)}
unrenderedFeatures	{Object} hash of features, keyed by feature.id, that the renderer failed to draw
reportError	{Boolean} report friendly error message when loading of renderer fails.
style	{Object} Default style for the layer
styleMap	{OpenLayers.StyleMap}
strategies	{Array(OpenLayers.Strategy})} Optional list of strategies for the layer.
protocol	{OpenLayers.Protocol} Optional protocol for the layer.
renderers	{Array(String)} List of supported Renderer classes.
renderer	{OpenLayers.Renderer}
rendererOptions	{Object} Options for the renderer.
geometryType	{String} geometryType allows you to limit the types of geometries this layer supports.
drawn	{Boolean} Whether the Vector Layer features have been drawn yet.
Constructor
OpenLayers.Layer.Vector	Create a new vector layer
Functions
destroy	Destroy this layer
refresh	Ask the layer to request features again and redraw them.
assignRenderer	Iterates through the available renderer implementations and selects and assigns the first one whose “supported()” function returns true.
displayError	Let the user know their browser isn’t supported.
setMap	The layer has been added to the map.
afterAdd	Called at the end of the map.addLayer sequence.
removeMap	The layer has been removed from the map.
onMapResize	Notify the renderer of the change in size.
moveTo	Reset the vector layer’s div so that it once again is lined up with the map.
display	Hide or show the Layer
addFeatures	Add Features to the layer.
removeFeatures	Remove features from the layer.
destroyFeatures	Erase and destroy features on the layer.
drawFeature	Draw (or redraw) a feature on the layer.
eraseFeatures	Erase features from the layer.
getFeatureFromEvent	Given an event, return a feature if the event occurred over one.
getFeatureById	Given a feature id, return the feature if it exists in the features array
onFeatureInsert	method called after a feature is inserted.
preFeatureInsert	method called before a feature is inserted.
getDataExtent	Calculates the max extent which includes all of the features.

Constants

EVENT_TYPES

{Array(String)} Supported application event types. 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

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

Supported map event types (in addition to those from OpenLayers.Layer)

beforefeatureadded	Triggered before a feature is added. Listeners will receive an object with a feature property referencing the feature to be added. To stop the feature from being added, a listener should return false.
beforefeaturesadded	Triggered before an array of features is added. Listeners will receive an object with a features property referencing the feature to be added. To stop the features from being added, a listener should return false.
featureadded	Triggered after a feature is added. The event object passed to listeners will have a feature property with a reference to the added feature.
featuresadded	Triggered after features are added. The event object passed to listeners will have a features property with a reference to an array of added features.
beforefeatureremoved	Triggered before a feature is removed. Listeners will receive an object with a feature property referencing the feature to be removed.
featureremoved	Triggerd after a feature is removed. The event object passed to listeners will have a feature property with a reference to the removed feature.
featuresremoved	Triggered after features are removed. The event object passed to listeners will have a features property with a reference to an array of removed features.
featureselected	Triggered after a feature is selected. Listeners will receive an object with a feature property referencing the selected feature.
featureunselected	Triggered after a feature is unselected. Listeners will receive an object with a feature property referencing the unselected feature.
beforefeaturemodified	Triggered when a feature is selected to be modified. Listeners will receive an object with a feature property referencing the selected feature.
featuremodified	Triggered when a feature has been modified. Listeners will receive an object with a feature property referencing the modified feature.
afterfeaturemodified	Triggered when a feature is finished being modified. Listeners will receive an object with a feature property referencing the modified feature.
vertexmodified	Triggered when a vertex within any feature geometry has been modified. Listeners will receive an object with a feature property referencing the modified feature, a vertex property referencing the vertex modified (always a point geometry), and a pixel property referencing the pixel location of the modification.
sketchstarted	Triggered when a feature sketch bound for this layer is started. Listeners will receive an object with a feature property referencing the new sketch feature and a vertex property referencing the creation point.
sketchmodified	Triggered when a feature sketch bound for this layer is modified. Listeners will receive an object with a vertex property referencing the modified vertex and a feature property referencing the sketch feature.
sketchcomplete	Triggered when a feature sketch bound for this layer is complete. Listeners will receive an object with a feature property referencing the sketch feature. By returning false, a listener can stop the sketch feature from being added to the layer.
refresh	Triggered when something wants a strategy to ask the protocol for a new set of features.

Properties

isBaseLayer

{Boolean} The layer is a base layer. Default is true. Set this property in the layer options

isFixed

{Boolean} Whether the layer remains in one place while dragging the map.

isVector

{Boolean} Whether the layer is a vector layer.

features

{Array(OpenLayers.Feature.Vector)}

selectedFeatures

{Array(OpenLayers.Feature.Vector)}

unrenderedFeatures

{Object} hash of features, keyed by feature.id, that the renderer failed to draw

reportError

{Boolean} report friendly error message when loading of renderer fails.

style

{Object} Default style for the layer

styleMap

{OpenLayers.StyleMap}

strategies

{Array(OpenLayers.Strategy})} Optional list of strategies for the layer.

protocol

{OpenLayers.Protocol} Optional protocol for the layer.

renderers

{Array(String)} List of supported Renderer classes. Add to this list to add support for additional renderers. This list is ordered: the first renderer which returns true for the ‘supported()’ method will be used, if not defined in the ‘renderer’ option.

renderer

{OpenLayers.Renderer}

rendererOptions

{Object} Options for the renderer. See {OpenLayers.Renderer} for supported options.

geometryType

{String} geometryType allows you to limit the types of geometries this layer supports. This should be set to something like “OpenLayers.Geometry.Point” to limit types.

drawn

{Boolean} Whether the Vector Layer features have been drawn yet.

Constructor

OpenLayers.Layer.Vector

Create a new vector layer

Parameters

name	{String} A name for the layer
options	{Object} Optional object with non-default properties to set on the layer.

Returns

{OpenLayers.Layer.Vector} A new vector layer

Functions

destroy

destroy: function()

Destroy this layer

refresh

refresh: function( obj )

Ask the layer to request features again and redraw them. Triggers the refresh event if the layer is in range and visible.

Parameters

obj	{Object} Optional object with properties for any listener of the refresh event.

assignRenderer

assignRenderer: function()

Iterates through the available renderer implementations and selects and assigns the first one whose “supported()” function returns true.

displayError

displayError: function()

Let the user know their browser isn’t supported.

setMap

setMap: function( map )

The layer has been added to the map.

If there is no renderer set, the layer can’t be used. Remove it. Otherwise, give the renderer a reference to the map and set its size.

Parameters

map	{OpenLayers.Map}

afterAdd

afterAdd: function()

Called at the end of the map.addLayer sequence. At this point, the map will have a base layer. Any autoActivate strategies will be activated here.

removeMap

removeMap: function( map )

The layer has been removed from the map.

Parameters

map	{OpenLayers.Map}

onMapResize

onMapResize: function()

Notify the renderer of the change in size.

moveTo

moveTo: function( bounds,
zoomChanged,
dragging )

Reset the vector layer’s div so that it once again is lined up with the map. Notify the renderer of the change of extent, and in the case of a change of zoom level (resolution), have the renderer redraw features.

If the layer has not yet been drawn, cycle through the layer’s features and draw each one.

Parameters

bounds	{OpenLayers.Bounds}
zoomChanged	{Boolean}
dragging	{Boolean}

display

display: function( display )

Hide or show the Layer

Parameters

display

{Boolean}

addFeatures

addFeatures: function( features,
options )

Add Features to the layer.

Parameters

features	{Array(OpenLayers.Feature.Vector)}
options	{Object}

removeFeatures

removeFeatures: function( features,
options )

Remove features from the layer. This erases any drawn features and removes them from the layer’s control. The beforefeatureremoved and featureremoved events will be triggered for each feature. The featuresremoved event will be triggered after all features have been removed. To supress event triggering, use the silent option.

Parameters

features	{Array(OpenLayers.Feature.Vector)} List of features to be removed.
options	{Object} Optional properties for changing behavior of the removal.

Valid options

silent

{Boolean} Supress event triggering. Default is false.

destroyFeatures

destroyFeatures: function( features,
options )

Erase and destroy features on the layer.

Parameters

features	{Array(OpenLayers.Feature.Vector)} An optional array of features to destroy. If not supplied, all features on the layer will be destroyed.
options	{Object}

drawFeature

drawFeature: function( feature,
style )

Draw (or redraw) a feature on the layer. If the optional style argument is included, this style will be used. If no style is included, the feature’s style will be used. If the feature doesn’t have a style, the layer’s style will be used.

This function is not designed to be used when adding features to the layer (use addFeatures instead). It is meant to be used when the style of a feature has changed, or in some other way needs to visually updated after it has already been added to a layer. You must add the feature to the layer for most layer-related events to happen.

Parameters

feature	{OpenLayers.Feature.Vector}
style	{Object} Symbolizer hash or {String} renderIntent

eraseFeatures

eraseFeatures: function( features )

Erase features from the layer.

Parameters

features

{Array(OpenLayers.Feature.Vector)}

getFeatureFromEvent

getFeatureFromEvent: function( evt )

Given an event, return a feature if the event occurred over one. Otherwise, return null.

Parameters

evt

{Event}

Returns

{OpenLayers.Feature.Vector} A feature if one was under the event.

getFeatureById

getFeatureById: function( featureId )

Given a feature id, return the feature if it exists in the features array

Parameters

featureId

{String}

Returns

{OpenLayers.Feature.Vector} A feature corresponding to the given featureId

onFeatureInsert

onFeatureInsert: function( feature )

method called after a feature is inserted. Does nothing by default. Override this if you need to do something on feature updates.

Paarameters

feature

{OpenLayers.Feature.Vector}

preFeatureInsert

preFeatureInsert: function( feature )

method called before a feature is inserted. Does nothing by default. Override this if you need to do something when features are first added to the layer, but before they are drawn, such as adjust the style.

Parameters

feature

{OpenLayers.Feature.Vector}

getDataExtent

getDataExtent: function ()

Calculates the max extent which includes all of the features.

Returns

{OpenLayers.Bounds}