# Module: ol/layer/Heatmap

This documentation is for OpenLayers v10.9.0. The latest is v.

## ol/layer/Heatmap

### Classes

Heatmap

### Type Definitions

#### HeatmapEventTypes{'change:blur'} {'change:radius'} {'change:gradient'}

#### Options{Object}

  ##### Properties:

  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` | NumberExpression (defaults to 8) | Radius size in pixels. Note that for LineStrings, the width of the line will be double the radius.
  `blur` | NumberExpression (defaults to 15) | Blur size in pixels. This is added to the `radius` parameter above to create the final size of the blur effect.
  `weight` | WeightExpression (defaults to 'weight') | The feature attribute to use for the weight. This also supports expressions returning a number 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).
  `filter` | BooleanExpression | undefined | Optional filter expression.
  `variables` | Object.<string, (number|Array.<number>|string|boolean)> | undefined | Variables used in expressions (optional)
  `source` | VectorSourceType | undefined | Point source.
  `properties` | Object.<string, *> | undefined | Arbitrary observable properties. Can be accessed with `#get()` and `#set()`.

#### WeightExpression()

layer/Heatmap.js, line 36