Class: Heatmap

ol/layer/Heatmap~Heatmap


import Heatmap from 'ol/layer/Heatmap';

Layer for rendering vector data as a heatmap. Note that any property set in the options is set as a BaseObject property on the layer object; for example, setting title: 'My Title' in the options means that title is observable, and has get/set accessors.

new Heatmap(options)

Name Type Description
className string (defaults to 'ol-layer')

A CSS class name to set to the layer element.

opacity number (defaults to 1)

Opacity (0, 1).

visible boolean (defaults to true)

Visibility.

extent Extent | undefined

The bounding extent for layer rendering. The layer will not be rendered outside of this extent.

zIndex number | undefined

The z-index for layer rendering. At rendering time, the layers will be ordered, first by Z-index and then by position. When undefined, a zIndex of 0 is assumed for layers that are added to the map's layers collection, or Infinity when the layer's setMap() method was used.

minResolution number | undefined

The minimum resolution (inclusive) at which this layer will be visible.

maxResolution number | undefined

The maximum resolution (exclusive) below which this layer will be visible.

minZoom number | undefined

The minimum view zoom level (exclusive) above which this layer will be visible.

maxZoom number | undefined

The maximum view zoom level (inclusive) at which this layer will be visible.

gradient Array.<string> (defaults to ['#00f', '#0ff', '#0f0', '#ff0', '#f00'])

The color gradient of the heatmap, specified as an array of CSS color strings.

radius number (defaults to 8)

Radius size in pixels.

blur number (defaults to 15)

Blur size in pixels.

weight string | function (defaults to 'weight')

The feature attribute to use for the weight or a function that returns a weight from a feature. Weight values should range from 0 to 1 (and values outside will be clamped to that range).

source VectorSource<Point> | undefined

Point source.

properties Object.<string, *> | undefined

Arbitrary observable properties. Can be accessed with #get() and #set().

Fires:

Extends

Observable Properties

Name Type Settable ObjectEvent type Description
blur number yes change:blur

Blur size in pixels.

extent Extent | undefined yes change:extent

The layer extent.

gradient Array.<string> yes change:gradient

Colors.

maxResolution number yes change:maxresolution

The maximum resolution of the layer.

maxZoom number yes change:maxzoom

The maximum zoom level of the layer.

minResolution number yes change:minresolution

The minimum resolution of the layer.

minZoom number yes change:minzoom

The minimum zoom level of the layer.

opacity number yes change:opacity

The opacity of the layer.

radius number yes change:radius

Radius size in pixel.

source SourceType | null yes change:source

The layer source (or null if not yet set).

visible boolean yes change:visible

The visibility of the layer.

zIndex number yes change:zindex

The Z-index of the layer.

Methods

Increases the revision counter and dispatches a 'change' event.

dispatchEvent(event){boolean | undefined} inherited

Dispatches an event and calls all listeners listening for events of this type. The event parameter can either be a string or an Object with a type property.

Name Type Description
event BaseEvent | string

Event object.

Returns:
false if anyone called preventDefault on the event object or if any of the listeners returned false.

Gets a value.

Name Type Description
key string

Key name.

Returns:
Value.

getBlur(){number}

Return the blur size in pixels.

Returns:
Blur size in pixels.

getExtent(){Extent | undefined} inherited

Return the extent of the layer or undefined if it will be visible regardless of extent.

Returns:
The layer extent.

getFeatures(pixel){PromiseFeature>>} inherited

Get the topmost feature that intersects the given pixel on the viewport. Returns a promise that resolves with an array of features. The array will either contain the topmost feature when a hit was detected, or it will be empty.

The hit detection algorithm used for this method is optimized for performance, but is less accurate than the one used in map.getFeaturesAtPixel(). Text is not considered, and icons are only represented by their bounding box instead of the exact image.

Name Type Description
pixel Pixel

Pixel.

Returns:
Promise that resolves with an array of features.

getGradient(){Array.<string>}

Return the gradient colors as array of strings.

Returns:
Colors.

getKeys(){Array.<string>} inherited

Get a list of object property names.

Returns:
List of property names.

getMaxResolution(){number} inherited

Return the maximum resolution of the layer.

Returns:
The maximum resolution of the layer.

getMaxZoom(){number} inherited

Return the maximum zoom level of the layer.

Returns:
The maximum zoom level of the layer.

getMinResolution(){number} inherited

Return the minimum resolution of the layer.

Returns:
The minimum resolution of the layer.

getMinZoom(){number} inherited

Return the minimum zoom level of the layer.

Returns:
The minimum zoom level of the layer.

getOpacity(){number} inherited

Return the opacity of the layer (between 0 and 1).

Returns:
The opacity of the layer.

getProperties(){Object.<string, *>} inherited

Get an object of all property names and values.

Returns:
Object.

getRadius(){number}

Return the size of the radius in pixels.

Returns:
Radius size in pixel.

getRevision(){number} inherited

Get the version number for this object. Each time the object is modified, its version number will be incremented.

Returns:
Revision.

getSource(){SourceType | null} inherited

Get the layer source.

Returns:
The layer source (or null if not yet set).

getStyle(){StyleLike | null | undefined} inherited

Get the style for features. This returns whatever was passed to the style option at construction or to the setStyle method.

Returns:
Layer style.

getStyleFunction(){StyleFunction | undefined} inherited

Get the style function.

Returns:
Layer style function.

getVisible(){boolean} inherited

Return the visibility of the layer (true or false).

Returns:
The visibility of the layer.

getZIndex(){number} inherited

Return the Z-index of the layer, which is used to order layers before rendering. The default Z-index is 0.

Returns:
The Z-index of the layer.

on(type, listener){EventsKey | Array<EventsKey>} inherited

Listen for a certain type of event.

Name Type Description
type string | Array.<string>

The event type or array of event types.

listener function

The listener function.

Returns:
Unique key for the listener. If called with an array of event types as the first argument, the return will be an array of keys.

once(type, listener){EventsKey | Array<EventsKey>} inherited

Listen once for a certain type of event.

Name Type Description
type string | Array.<string>

The event type or array of event types.

listener function

The listener function.

Returns:
Unique key for the listener. If called with an array of event types as the first argument, the return will be an array of keys.

set(key, value, silent) inherited

Sets a value.

Name Type Description
key string

Key name.

value *

Value.

silent boolean | undefined

Update without triggering an event.

setBlur(blur)

Set the blur size in pixels.

Name Type Description
blur number

Blur size in pixels.

setExtent(extent) inherited

Set the extent at which the layer is visible. If undefined, the layer will be visible at all extents.

Name Type Description
extent Extent | undefined

The extent of the layer.

setGradient(colors)

Set the gradient colors as array of strings.

Name Type Description
colors Array.<string>

Gradient.

Sets the layer to be rendered on top of other layers on a map. The map will not manage this layer in its layers collection. This is useful for temporary layers. To remove an unmanaged layer from the map, use #setMap(null).

To add the layer to a map and have it managed by the map, use addLayer instead.

Name Type Description
map Map | null

Map.

setMaxResolution(maxResolution) inherited

Set the maximum resolution at which the layer is visible.

Name Type Description
maxResolution number

The maximum resolution of the layer.

setMaxZoom(maxZoom) inherited

Set the maximum zoom (exclusive) at which the layer is visible. Note that the zoom levels for layer visibility are based on the view zoom level, which may be different from a tile source zoom level.

Name Type Description
maxZoom number

The maximum zoom of the layer.

setMinResolution(minResolution) inherited

Set the minimum resolution at which the layer is visible.

Name Type Description
minResolution number

The minimum resolution of the layer.

setMinZoom(minZoom) inherited

Set the minimum zoom (inclusive) at which the layer is visible. Note that the zoom levels for layer visibility are based on the view zoom level, which may be different from a tile source zoom level.

Name Type Description
minZoom number

The minimum zoom of the layer.

setOpacity(opacity) inherited

Set the opacity of the layer, allowed values range from 0 to 1.

Name Type Description
opacity number

The opacity of the layer.

setProperties(values, silent) inherited

Sets a collection of key-value pairs. Note that this changes any existing properties and adds new ones (it does not remove any existing properties).

Name Type Description
values Object.<string, *>

Values.

silent boolean | undefined

Update without triggering an event.

setRadius(radius)

Set the size of the radius in pixels.

Name Type Description
radius number

Radius size in pixel.

setSource(source) inherited

Set the layer source.

Name Type Description
source SourceType | null

The layer source.

Set the style for features. This can be a single style object, an array of styles, or a function that takes a feature and resolution and returns an array of styles. If set to null, the layer has no style (a null style), so only features that have their own styles will be rendered in the layer. Call setStyle() without arguments to reset to the default style. See the ol/style/Style module for information on the default style.

If your layer has a static style, you can use "flat" style object literals instead of using the Style and symbolizer constructors (Fill, Stroke, etc.). See the documentation for the flat style types to see what properties are supported.

Name Type Description
style StyleLike | FlatStyleLike | null | undefined

Layer style.

setVisible(visible) inherited

Set the visibility of the layer (true or false).

Name Type Description
visible boolean

The visibility of the layer.

setZIndex(zindex) inherited

Set Z-index of the layer, which is used to order layers before rendering. The default Z-index is 0.

Name Type Description
zindex number

The z-index of the layer.

un(type, listener) inherited

Unlisten for a certain type of event.

Name Type Description
type string | Array.<string>

The event type or array of event types.

listener function

The listener function.

unset(key, silent) inherited

Unsets a property.

Name Type Description
key string

Key name.

silent boolean | undefined

Unset without triggering an event.