# maptalks.heatmap

**Repository Path**: yhjworkspace/maptalks.heatmap

## Basic Information

- **Project Name**: maptalks.heatmap
- **Description**: A heatmap layer plugin for maptalks.js
- **Primary Language**: JavaScript
- **License**: MIT
- **Default Branch**: master
- **Homepage**: None
- **GVP Project**: No

## Statistics

- **Stars**: 0
- **Forks**: 0
- **Created**: 2019-07-02
- **Last Updated**: 2021-10-01

## Categories & Tags

**Categories**: Uncategorized

**Tags**: None

## README

# maptalks.heatmap

[![CircleCI](https://circleci.com/gh/maptalks/maptalks.heatmap/tree/master.svg?style=shield)](https://circleci.com/gh/maptalks/maptalks.heatmap)
[![NPM Version](https://img.shields.io/npm/v/maptalks.heatmap.svg)](https://github.com/maptalks/maptalks.heatmap)

A plugin of [maptalks.js](https://github.com/maptalks/maptalks.js) to draw heatmap on maps, based on mourner's [simpleheat](https://github.com/mourner/simpleheat).

![screenshot](https://cloud.githubusercontent.com/assets/13678919/25303099/98ad71fa-277e-11e7-8722-a3435d11e1f5.jpg)

## Examples

* A heatmap of [50000 points](https://maptalks.github.io/maptalks.heatmap/demo/). (data from [Leaflet.Heat](https://github.com/Leaflet/Leaflet.heat))

## Install
  
* Install with npm: ```npm install maptalks.heatmap```. 
* Download from [dist directory](https://github.com/maptalks/maptalks.heatmap/tree/gh-pages/dist).
* Use unpkg CDN: ```https://unpkg.com/maptalks.heatmap/dist/maptalks.heatmap.min.js```

## Usage

As a plugin, ```maptalks.heatmap``` must be loaded after ```maptalks.js``` in browsers.

### Vanilla Javascript
```html
<script type="text/javascript" src="https://unpkg.com/maptalks/dist/maptalks.min.js"></script>
<script type="text/javascript" src="https://unpkg.com/maptalks.heatmap/dist/maptalks.heatmap.min.js"></script>
<script>
var data = [[0, 0, 0.3], [0, 0, 0.4], [0, 0, 0.4]];
var heatLayer = new maptalks.HeatLayer('heat', data).addTo(map);
</script>
```

### ES6

```javascript
import { HeatLayer } from 'maptalks.heatmap';
const data = [[0, 0, 0.3], [0, 0, 0.4], [0, 0, 0.4]];
const heatLayer = new HeatLayer('heat', data).addTo(map);
```

## Supported Browsers

IE 9-11, Chrome, Firefox, other modern and mobile browsers.

## API Reference

### `Constructor`

```HeatmapLayer``` is a subclass of [maptalks.Layer](https://maptalks.github.io/maptalks.js/api/0.x/Layer.html) and inherits all the methods of its parent.

```javascript
new maptalks.HeatmapLayer(id, data, options)
```

* id **String** layer id
* data **Array[]** layer data: [[x, y, value], [x, y, value]..]
* options **Object** options
    * max **Number** max data value (1 by default) 
    * radius **Number** point radius(25 by default)
    * blur **Number**  blur radius(15 by default)
    * minOpacity **Number** minimum point opacity (0.05 by default)
    * heatValueScale **Number** the scale value to multiply with heat data (1 by default)
    * gradient **Object** set gradient colors as {\<stop\>: '\<color\>'}, default by { 0.4: 'blue', 0.6: 'cyan', 0.7: 'lime', 0.8: 'yellow', 1.0: 'red' }
    * Other options defined in [maptalks.Layer](https://maptalks.github.io/maptalks.js/api/0.x/Layer.html)

### `config(key, value)`

config layer's options and redraw the layer if necessary

```javascript
heatLayer.config('max', 10);
heatLayer.config({
    'radius' : 80,
    'blur' : 30,
    'gradient' : {0.4: 'blue', 0.65: 'lime', 1: 'red'}
});
```

**Returns** `this`

### `getData`

get layer's data

**Returns** `Array[]`

### `setData(data)`

set new data

* data **Array[]** data to set

**Returns** `this`

### `addPoint(point)`

add more points

* point **Array[]** points to add, [[x, y, value], [x, y, value]..]

**Returns** `this`

### `redraw()`

**Returns** `this`

### `isEmpty()`

**Returns** `Boolean`

### `clear()`

**Returns** `this`

### `toJSON(options)`

export the layer's JSON.

* options **Object** options
    * clipExtent **maptalks.Extent** the extent to clip

```javascript
// only export points in map's current extent.
heatLayer.toJSON({
    'clipExtent' : map.getExtent()
});
```

**Returns** `Object`

## Contributing

We welcome any kind of contributions including issue reportings, pull requests, documentation corrections, feature requests and any other helps.

## Develop

The only source file is ```index.js```.

It is written in ES6, transpiled by [babel](https://babeljs.io/) and tested with [mocha](https://mochajs.org) and [expect.js](https://github.com/Automattic/expect.js).

### Scripts

* Install dependencies
```shell
$ npm install
```

* Watch source changes and generate runnable bundle repeatedly
```shell
$ gulp watch
```

* Tests
```shell
$ npm test
```

* Watch source changes and run tests repeatedly
```shell
$ gulp tdd
```

* Package and generate minified bundles to dist directory
```shell
$ gulp minify
```

* Lint
```shell
$ npm run lint
```