mapbox-gl-flatgeobuf

A little library provides a tiled approach to consuming flatgeobuf files.

Note This library is compatible with both mapbox-gl and maplibre-gl.

Installation

npm install mapbox-gl-flatgeobuf

Basic Usage

  import FlatGeobuf from 'mapbox-gl-flatgeobuf'

  const fsSourceId = "fgb-src";

  new FlatGeobuf(fsSourceId, map, {
    url: "https://flatgeobuf.org/test/data/UScounties.fgb",
    minZoom: 8,
    idProperty: "FIPS",
  });

  map.addLayer({
    id: "fill-lyr",
    source: fsSourceId,
    type: "fill",
    paint: {
      "fill-opacity": 0.5,
      "fill-color": "#B42222",
    },
  });

API

This library exposes a single FlatGeobuf class

Constructor Options

| Option | Type | Description | --- | --- | --- | sourceId | String required | A string | | map | Object required | A mapbox-gl or maplibre-gl map instance. | | flatGeobufOptions | Object required | A range of options which will be used to access the flatgeobuf file. See below. | | geojsonSourceOptions | Object | A object which will be passed to the creation of the mapbox-gl geojson source |

FlatGeobuf Options

| Option | Type | Default | Description | --- | --- | --- | --- | url | String required | | The url of the flatgeobuf file eg https://flatgeobuf.org/test/data/UScounties.fgb. | | minZoom | Number required | 7 | The zoom level to start requesting tiles. | | idProperty | String required | | An id field in the data to help minimise duplicate features being added to the map |

Methods

| Method | Description | ------- | ----------- | destroySource() | Important The destroySource() method removes the source from the map and associated event listeners for retrieving data which request data as the map is panned, so it's important to call this method if removing the layer from the map completely. | | disableRequests() | Important The disableRequests() method temporarily disables the associated event listeners for retrieving data which request data as the map is panned, you may want to call this if you toggle your layer off. | | enableRequests() | Important The enableRequests() method enables the associated event listeners for retrieving data which request data as the map is panned. By default this is called by the constructor. |

Example of disabling and enabling requests

It would be nice if disabling/enabling of requests happened automatically but unfortunantly I haven't found a way to make that happen because of how sources and layers are managed in mapbox-gl.

  const fsSourceId = "fgb-src";

  const fgb = new FlatGeobuf(fsSourceId, map, {
    url: "https://flatgeobuf.org/test/data/UScounties.fgb",
    minZoom: 8,
    idProperty: "FIPS",
  });
    
  const fgLyrId = 'fs-fill-lyr'
  map.addLayer({
    'id': fgLyrId,
    'source': fsSourceId,
    'type': 'fill',
    'paint': {
      'fill-opacity': 0.5,
      'fill-color': '#B42222'
    }
  })

  function hideFsLayer () {
      map.setLayoutProperty(fgLyrId, 'visibility', 'none')
      fgb.disableRequests()
  }

  function showFsLayer () {
      map.setLayoutProperty(fgLyrId, 'visibility', 'visible')
      fgb.enableRequests()
  }

  function removeFsCompletelyFromMap () {
    map.removeLayer(fgLyrId)
    fgb.destroySource()
  }