Add support for MLT #6570

HarelM · 2025-10-15T09:00:20Z

Launch Checklist

Resolves Support MapLibre Tiles (MLT) #6258

This PR will introduce support for MLT format.

Confirm your changes do not include backports from Mapbox projects (unless with compliant license) - if you are not sure about this, please ask!
Briefly describe the changes in this PR.
Link to related issues.
Write tests for all new functionality.
Add an entry to CHANGELOG.md under the ## main section.

HarelM · 2025-10-15T09:02:08Z

@Salkin975 I've opened the following branch for integration, and this PR to see that we keep this branch working and up-to-date with the main branch.:
https://github.com/maplibre/maplibre-gl-js/tree/mlt

I tried to copy over the code from your branch but I'm not sure this is the right approach to solve it.
Most of the code is duplicated between mlt and vector source when there's no real need to copy it.

I would recommend as an initial step to only try and make mlt work in maplibre without optimizing the buckets and other things.
Once we have it working with some basic tests for lines, fill, symbols etc, we can start implementing the optimizations that are needed.
What do you think?

codecov · 2025-10-15T09:03:04Z

Codecov Report

❌ Patch coverage is 69.69697% with 30 lines in your changes missing coverage. Please review.
✅ Project coverage is 92.20%. Comparing base (e832ffa) to head (06d908b).
⚠️ Report is 4 commits behind head on main.

Files with missing lines	Patch %	Lines
src/source/vector_tile_mlt.ts	67.04%	29 Missing ⚠️
src/source/vector_tile_worker_source.ts	80.00%	1 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #6570      +/-   ##
==========================================
- Coverage   92.29%   92.20%   -0.10%     
==========================================
  Files         283      284       +1     
  Lines       23558    23652      +94     
  Branches     5001     5025      +24     
==========================================
+ Hits        21744    21808      +64     
- Misses       1814     1844      +30

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socket-security · 2025-10-15T18:01:40Z

Review the following changes in direct dependencies. Learn more about Socket for GitHub.

Diff	Package	Supply Chain Security	Vulnerability	Quality	Maintenance	License
	@maplibre/mlt@1.1.0

View full report

* add basic render tests for mlt feature rendering * add city and country label rendering test * change test path * simplify styles * simplify styles by removing feature filters * removed allowed --------- Co-authored-by: Niklas Greindl <niklas.greindl.@rohde-schwarz.com>

package.json

HarelM · 2025-10-29T19:20:44Z

Unfortunately, coverage report does not work on the worker as is, and there might be other configuration needed in order to make it work, but the code is fully covered.

src/source/vector_tile_source.ts

HarelM · 2025-11-02T19:25:22Z

For future reference, I've used the following page to check the geometry rendering and conversion,
I'll see if I can add some test to cover this functionality.

<!DOCTYPE html>
<html lang="en">
<head>
    <title>Display a map</title>
    <meta property="og:description" content="Initialize a map in an HTML element with MapLibre GL JS." />
    <meta charset='utf-8'>
    <meta name="viewport" content="width=device-width, initial-scale=1">
    <link rel='stylesheet' href='../../dist/maplibre-gl.css' />
    <script src='../../dist/maplibre-gl-dev.js'></script>
    <style>
        body { margin: 0; padding: 0; }
        html, body, #map { height: 100%; }
    </style>
</head>
<body>
<div id="map"></div>
<script>
    const map = new maplibregl.Map({
        container: 'map', // container id
        style: 'https://harelm.github.io/demotiles/tiles-mlt/plain.json', // style URL
        center: [0, 0], // starting position [lng, lat]
        zoom: 1, // starting zoom
        maplibreLogo: true
    });

    map.once('load', () => {
        map.addSource('gj', {
            type: 'geojson',
            data: []
        });
        map.addLayer({
            id: 'filll',
            type: 'fill',
            source: 'gj',
            filter: ["==", "$type", "Polygon"],
            paint: {
                'fill-color': 'red'
            }
        });

        map.addLayer({
            id: 'lineee',
            type: 'line',
            source: 'gj',
            filter: ["==", "$type", "LineString"],
            paint: {
                'line-color': 'blue'
            }
        });

        map.addLayer({
            id: 'pointtt',
            type: 'circle',
            source: 'gj',
            filter: ["==", "$type", "Point"],
            paint: {
                'circle-color': 'green'
            }
        });

        map.on("mousemove", (e) => {
            const features = map.queryRenderedFeatures(e.point);
            if (features.length > 0) {
                console.log(features.map(f => f.geometry));
                map.getSource('gj').setData({ 
                    type: 'FeatureCollection',
                    features: features.filter(f => f.source !== 'gj')
                })
            }
        })
    })
</script>
</body>
</html>

* Initial mlt support hack * Update min test * Update build test * Use released package instead of mocks * Update mlt package to latest version * Fix lint * Initial implementation * Update package version * Fix lint * Update package and relevant code. * Update mltpackage to latest * Update mlt to latest version * Add basic render tests for mlt (maplibre#6631) * add basic render tests for mlt feature rendering * add city and country label rendering test * change test path * simplify styles * simplify styles by removing feature filters * removed allowed --------- Co-authored-by: Niklas Greindl <niklas.greindl.@rohde-schwarz.com> * treat mlt as binary data * Update mlt tiles * Update changelog * Update build size, this will probably change in next version of mlt * Move mlt vector worker to parent directory. * Add support for queryrenderedfeatures * Update to latest mlt package * Add tests to feature index. * Fix lint, simplify test * Add html example, still without an image. * Update mlt to latest version * Rename mlt to match other files in that folder * Update expected bytes. * Update link to where the style is. * Add image for the docs --------- Co-authored-by: Niklas Greindl <154528139+Salkin975@users.noreply.github.com> Co-authored-by: Niklas Greindl <niklas.greindl.@rohde-schwarz.com>

HarelM added 2 commits October 15, 2025 11:51

Initial mlt support hack

ea12721

Merge branch 'main' into mlt

cbce2c3

Update min test

3a809fc

HarelM mentioned this pull request Oct 15, 2025

Add support for Mlt tile format #6567

Closed

10 tasks

HarelM added 2 commits October 15, 2025 12:16

Update build test

93b93b1

Use released package instead of mocks

3586758

HarelM added 7 commits October 16, 2025 13:28

Update mlt package to latest version

9145092

Fix lint

ed703c6

Initial implementation

3b33d0b

Update package version

b8bb41b

Fix lint

d38de93

Update package and relevant code.

e2ff715

Merge branch 'main' into mlt

1a1acf3

This was referenced Oct 22, 2025

Initial support for maplibre vector tiles onthegomap/planetiler#1355

Merged

Typescript decoder fails to decode geometries for some features maplibre/maplibre-tile-spec#640

Closed

HarelM added 2 commits October 24, 2025 14:23

Update mltpackage to latest

4b8a16b

Update mlt to latest version

d7b173e

HarelM mentioned this pull request Oct 27, 2025

Call for Submissions: Oct 2025 Newsletter maplibre/maplibre.github.io#478

Closed

Salkin975 and others added 6 commits October 29, 2025 20:23

treat mlt as binary data

7c61b71

Merge branch 'main' into mlt

69750e2

Update mlt tiles

ac4ee92

Update changelog

1af05f4

Update build size, this will probably change in next version of mlt

b77dcec

HarelM commented Oct 29, 2025

View reviewed changes

package.json Outdated Show resolved Hide resolved

Move mlt vector worker to parent directory.

7e29a69

HarelM marked this pull request as ready for review October 29, 2025 19:20

HarelM requested review from birkskyum and mwilsnd October 29, 2025 19:21

acalcutt reviewed Nov 2, 2025

View reviewed changes

src/source/vector_tile_source.ts Show resolved Hide resolved

Merge branch 'main' into mlt

e8ff790

HarelM added 6 commits November 2, 2025 21:27

Add support for queryrenderedfeatures

58e86d4

Update to latest mlt package

dfe5cb0

Add tests to feature index.

4f98c00

Fix lint, simplify test

6331cf0

Merge branch 'main' into mlt

e2e6f01

Add html example, still without an image.

f3c10cd

HarelM requested review from louwers and wayofthefuture November 4, 2025 06:55

mwilsnd approved these changes Nov 4, 2025

View reviewed changes

HarelM added 6 commits November 7, 2025 20:40

Merge branch 'main' into mlt

98789b9

Update mlt to latest version

7558f72

Rename mlt to match other files in that folder

80644f5

Update expected bytes.

5be732d

Update link to where the style is.

b80eaf6

Add image for the docs

06d908b

HarelM merged commit 689a3c2 into main Nov 8, 2025
27 checks passed

HarelM deleted the mlt branch November 8, 2025 22:44

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