@cascadian/react-map-gl
v2.0.2
Published
A React wrapper for MapboxGL-js and overlay API.
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Maintainers
Readme
This project is new and the API may change.
npm install --save react-map-gl
Using with Browserify, Webpack etc
browserify
- react-map-gl is extensively tested withbrowserify
and works without configuration.webpack 1
- look at the deck.gl exhibits folder, demonstrating a working demo usingwebpack
.webpack 2
- The dev branch in this repo is based on webpack 2, look at the webpack config file in the main example.
In general, for non-browserify based environments, make sure you have read the instructions on the mapbox-gl-js README.
Example
import MapGL from 'react-map-gl';
<MapGL
width={400}
height={400}
latitude={37.7577}
longitude={-122.4376}
zoom={8}
onChangeViewport={viewport => {
const {latitude, longitude, zoom} = viewport;
// Optionally call `setState` and use the state to update the map.
}}
/>
Overlays
react-map-gl provides an overlay API so you can use the built-in visualization overlays, or create your own.
import {ScatterplotOverlay} from 'react-map-gl';
<MapGL {...viewport}>
<ScatterplotOverlay
{...viewport}
locations={locations}
dotRadius={4}
globalOpacity={1}
compositeOperation="screen" />
</MapGL>
Built-in overlays are: ChoroplethOverlay
, ScatterplotOverlay
, DraggablePointsOverlay
,
SVGOverlay
and CanvasOverlay
.
These overlays are currently not compatible with perspective mode.
deck.gl
deck.gl is a companion module to
react-map-gl
that provide a number of classic data visualization overlays
(scatterplots, choropleths etc) implemented in WebGL. These overlays are
suitable for large or dynamic data sets, or for use in perspective mode
applications.
Third-party
Third party overlays can also be created. For example, the heatmap-overlay uses webgl-heatmap to create geographic heatmaps.
import HeatmapOverlay from 'react-map-gl-heatmap-overlay';
import cities from 'example-cities';
<MapGL {...viewport}>
<HeatmapOverlay locations={cities} {...viewport} />
</MapGL>
Want to create and share your own overlay? Fork the react-map-gl-example-overlay project to get started.
Perspective Mode
Perspective mode is exposed using the pitch
and bearing
props
(both default to 0
), which will show the map "tilted" pitch
degrees
(overhead being 0 degrees), looking towards bearing
(0 degrees is north).
In addition, the perspectiveEnabled
prop (default: false
)
will activate mouse handlers that allow the user to change pitch
and
bearing
using the mouse while holding down any function key {command, shift, ctrl, alt}.
If perspectiveEnabled
is not set to true
then the user will not be able to
change the pitch and bearing, which means that the default props will show
an overhead map and only enable standard pan and zoom mouse actions on that map.
Considerations:
- Mapbox-gl-js limits the pitch to 60 degrees.
- When using pitch, several additional fields are passed in the onViewportChange callback, make sure to pass all received props back to the component.
- Not all overlays are compatible with perspective mode. For a set of overlays that do work with perspective mode, look at deck.gl.
Transitions
react-map-gl
does not expose the transition API for mapbox-gl-js
since it is
designed to be a stateless component.
Instead it is recommended to use a separate module like react-motion to animate properties.
<Motion style={{
latitude: spring(viewport.latitude, { stiffness: 170, damping: 26, precision: 0.000001 }),
longitude: spring(viewport.longitude, { stiffness: 170, damping: 26, precision: 0.000001 })
}}>
{({ latitude, longitude }) => <MapGL
{...viewport}
latitude={latitude}
longitude={longitude}
mapStyle={mapboxStyle}
/>}
</Motion>
ImmutableJS
The mapStyle
property of the MapGL
as well as several of the built in
overlay properties must be provided as
ImmutableJS objects. This allows
the library to be fast since computing changes to props only involves checking
if the immutable objects are the same instance.
Redux
If you're using redux, it is relatively simple to hook this component up to
store state in the redux state tree. The simplest way is to take all
properties passed to the onChangeViewport
function property and add them
directly into the store. This state can then be passed back to react-map-gl
without any transformation. You can use the package
redux-map-gl to save writing this
code yourself.
Development
Install project dependencies and start watching the examples:
npm start
You can now open your browser and navigate to http://localhost:9966/?access_token=TOKEN
,
where TOKEN
is a valid Mapbox access token.
Testing
Its difficult to write tests for this component because it uses WebGL.
There are some tests in the test folder but for the most part, as new
features are added, we typically test drive them by running npm start
and
play with the demos.
Contributing
Contributions are welcome. While not necessary, it can be helpful to check with maintainers before opening your PR. Also, you will need to complete a short open source contribution form before your pull request can be accepted.