React Map GL Draw

react-map-gl-draw is a react based drawing library tailored for react-map-gl.

Options

• mode (String, Optional)

  • EditorModes.READ_ONLY - Not interactive. This is the default mode.
  • EditorModes.SELECT - Lets you select, delete, and drag features.
  • EditorModes.EDITTING - Lets you select, delete, and drag vertices; and drag features.
  • EditorModes.DRAW_PATH - Lets you draw a GeoJson LineString feature.
  • EditorModes.DRAW_POLYGON - Lets you draw a GeoJson Polygon feature.
  • EditorModes.DRAW_POINT - Lets you draw a GeoJson Point feature.
  • EditorModes.DRAW_RECTANGLE - Lets you draw a Rectangle (represented as GeoJson Polygon feature).

• features (Feature[], Optional) - List of features in GeoJson format. If features are provided from users, then react-map-gl-draw respect the users' input, and therefore ignore any internal features. But if features are not provided, then react-map-gl-draw manages features internally, and users can access and manipulate the features by calling getFeatures, addFeatures, and deleteFeatures.

• selectedFeatureIndex (String, Optional) - Index of the selected feature.

• clickRadius (Number, Optional) - Radius to detect features around a hovered or clicked point. Default value is 0

• onSelect (Function, Optional) - callback when clicking a position under SELECT and EDITTING mode. Receives an object containing the following parameters

  • selectedFeature: selected feature. null if clicked an empty space.
  • selectedFeatureIndex: selected feature index.null if clicked an empty space.
  • editHandleIndex: selected editHandle index. null if clicked an empty space.
  • screenCoords: screen coordinates of the clicked position.
  • mapCoords: map coordinates of the clicked position.

• onUpdate (Function, Optional) - callback when anything is updated. Receives an object containing the following parameters

  • features (Feature[]) - the updated list of GeoJSON features.
  • editType (String) - addFeature, addPosition, finishMovePosition
  • editContext (Array) - list of edit objects, depend on editType, each object may contain featureIndexes, editHandleIndexes, screenCoords, mapCoords.

Feature object structure:

{
  id, // an unique identified generated inside react-map-gl-draw library 
  geometry: {
    coordinates, // latitude longitude pairs of the geometry points
    type // geojson type, one of `Point`, `LineString`, or `Polygon`
  },
  properties: {
    renderType, // Mainly used for styling, one of `Point`, `LineString`, `Polygon`, or `Rectangle`. Different from `geometry.type`. i.e. a rectangle's renderType is `Rectangle`, and `geometry.type` is `Polygon`. An incomplete (not closed) Polygon's renderType is `Polygon`, `geometry.type` is `LineString`
    ...otherProps // other properties user passed in
  }
}

Styling related options

• featureStyle (Object|Function, Optional) : Object - Either a style objects or a function to style a feature, function parameters are
  • feature: feature to style.
  • index: index of the feature.
  • state: one of SELECTED, HOVERED, INACTIVE, UNCOMMITTED, CLOSING.

Returns is a map of style objects passed to SVG path elements.

• featureShape (String|Function, Optional): if is a string, should be one of rect or circle. If is a function, will receive the following parameters

  • feature: feature to style.
  • index: index of the feature.
  • state: one of SELECTED, HOVERED, INACTIVE, UNCOMMITTED, CLOSING.

• editHandleStyle (Object|Function, Optional) : Object - Either a style objects or a function to style an `editHandle, function parameters are

  • feature: feature to style.
  • index: index of the editHandle vertex in the feature.
  • state: one of SELECTED, HOVERED, INACTIVE, UNCOMMITTED, CLOSING.
  • shape: shape resolved from editHandleShape.

Returns is a map of style objects passed to SVG circle or rect elements.

• editHandleShape (String|Function, Optional): if is a string, should be one of rect or circle. If is a function, will receive the following parameters
  • feature: feature to style.
  • index: index of the editHandle vertex in the feature.
  • state: one of SELECTED, HOVERED, INACTIVE, UNCOMMITTED, CLOSING.

Explanations

• Feature: any drawn shape, one of point, line, polygon or rectangle.
• EditHandle: vertex of the feature being edited.

State related concepts:

• INACTIVE: neither selected nor hovered, default state of a complete feature or editHandle.
• SELECTED: being clicked or dragged.
• HOVERED: hovered over by the mouse pointer.
• UNCOMMITTED: in the middle of drawing, not yet added to the feature being edited.
• CLOSING: closing a polygon.

Styling based on state:

As shown in the above image, for the feature currently being edited,

• featureStyle({feature, state: SELECTED}) will be applied to the committed parts of the feature. (Green strokes)
• editHandleStyle({state: SELECTED}) will be applied to the committed editHandle vertices. (Vertices with black stroke)
• featureStyle({feature, state: UNCOMMITTED}) will be applied to the uncommitted parts of the feature. (Gray stroke)
• editHandleStyle({state: UNCOMMITTED}) will be applied to the uncommitted editHandle vertex. (Gray vertex)

Methods

getFeatures

• Return a list of finished GeoJson features.

addFeatures (Feature | Feature[])

• Add a single or multiple GeoJson features to editor.

deleteDeatures (Feature | Feature[])

• Delete a single or multiple GeoJson features to editor.

Code Example

import React, { Component } from 'react';
import MapGL from 'react-map-gl';
import { Editor, EditorModes } from 'react-map-gl-draw';

const MODES = [
  { id: EditorModes.EDITING, text: 'Select and Edit Feature'},
  { id: EditorModes.DRAW_POINT, text: 'Draw Point'},
  { id: EditorModes.DRAW_PATH, text: 'Draw Polyline'},
  { id: EditorModes.DRAW_POLYGON, text: 'Draw Polygon'},
  { id: EditorModes.DRAW_RECTANGLE, text: 'Draw Rectangle'}
];

const DEFAULT_VIEWPORT = {
  width: 800,
  height: 600,
  longitude: -122.45,
  latitude: 37.78,
  zoom: 14
};

class App extends Component {
  state = {
    // map
    viewport: DEFAULT_VIEWPORT,
    // editor
    selectedMode: EditorModes.READ_ONLY
  };

  _switchMode = evt => {
    const selectedMode = evt.target.id;
    this.setState({
     selectedMode: selectedMode === this.state.selectedMode ? null : selectedMode
    });
  };

  _renderToolbar = () => {
    return (
      <div style={{position: absolute, top: 0, right: 0, maxWidth: '320px'}}>
        <select onChange={this._switchMode}>
          <option value="">--Please choose a mode--</option>
          {MODES.map(mode => <option value={mode.id}>{mode.text}</option>)}
        </select>
      </div>
    );
  };

  render() {
    const { viewport, selectedMode } = this.state;
    return (
      <MapGL
        {...viewport}
        width="100%"
        height="100%"
        mapStyle={'mapbox://styles/mapbox/light-v9'}
        onViewportChange={this.setState({ viewport })}
      >
        <Editor
          clickRadius={12}
          mode={selectedMode}
        />
        {this._renderToolbar()}
      </MapGL>
    );
  }
}