MLTLoader

Loader for the MapLibre Tile (MLT) geospatial tile format.

Loader	Characteristic
File Extension	.mlt
File Type	Binary
File Format	MapLibre Tile
MIME Types	application/vnd.maplibre-tile
Data Format	Geometry
Supported APIs	load, parse, parseSync
Worker Thread	Not available for this loader

Installation

npm install @loaders.gl/mlt
npm install @loaders.gl/core

Usage

import {MLTLoader} from '@loaders.gl/mlt';
import {load} from '@loaders.gl/core';

const tileFeatures = await load(url, MLTLoader);

Geometry in local tile space

By default, MLTLoader returns GeoJSON features using local tile coordinates in [0, 1] space:

import {MLTLoader} from '@loaders.gl/mlt';
import {load} from '@loaders.gl/core';

const geoJSONfeatures = await load(url, MLTLoader);

Geometry in WGS84

Set coordinates: 'wgs84' and provide the tile index to get longitude / latitude coordinates:

import {MLTLoader} from '@loaders.gl/mlt';
import {load} from '@loaders.gl/core';

const geoJSONfeatures = await load(url, MLTLoader, {
  mlt: {
    coordinates: 'wgs84',
    tileIndex: {
      x: tileX,
      y: tileY,
      z: tileZ
    }
  }
});

Output shapes

shape option	Output
'geojson' (default)	Feature[]
'geojson-table'	GeoJSONTable
'binary'	binary feature collection

Options

Option	Type	Default	Description
mlt.shape	'geojson-table' | 'geojson' | 'binary'	geojson	Output shape: GeoJSON array, GeoJSON table, or binary features
mlt.coordinates	'local' | 'wgs84'	local	Coordinate system for returned geometries
mlt.tileIndex	{x: number, y: number, z: number}	N/A	Required when coordinates is wgs84
mlt.layerProperty	string	layerName	Name of layer property added to feature properties
mlt.layers	string[]	N/A	Restrict parsing to specific tile layers

mlt.tileIndex is required for WGS84 output.

Additional examples

• Loaders.gl MLT website example.
• MLTSource for URL tile sets.

Attribution

MLTLoader implements loaders.gl integration, GeoJSON/binary shaping, and coordinate projection around the @maplibre/mlt decoder and the MapLibre Tile specification.