Interactive Web Map with Bootstrap, MapLibre GL JS, PMTiles, and GitHub Pages

This project demonstrates how to create an interactive web map for sharing geospatial projects. The web map consists of a single HTML file that uses Bootstrap to simplify styling. The map itself is rendered by MapLibre GL JS. Data is stored in the PMTiles format, a single-file format that simple to use and easy to deploy, making it a great choice for small to medium-sized datasets. Together, these packages make it possible to serve a fully-featured web map with static hosting services such as GitHub Pages.

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This project was created with the cookiecutter-bootstrap-maplibre-pmtiles template, originally authored by Philip Mathieu. If you like my work, consider buying me a coffee!

1. Prepare Dataset

This project assumes that you are working with a GeoJSON data source. If you are working with a different format, you will need to convert it to GeoJSON before proceeding. An example dataset is included in the data/example folder.

Converting to GeoJSON with GeoPandas

In the case that you are coming from a geopandas project, you can convert the GeoDataFrame to GeoJSON with the following code:

import geopandas as gpd

gdf = gpd.GeoDataFrame()
# ... add data to gdf ...
gdf.to_file("path/to/file.geojson", driver="GeoJSON")

There are lots of great tutorials on how to turn a regular Pandas DataFrame into a GeoDataFrame - for those and more documentation, see the geopandas documentation.

Converting to GeoJSON with GDAL

The "industry standard" tool for converting between geospatial data formats is GDAL. It requires a steep learning curve if you have never worked with geospatial formats before, but ultimately is a swiss army knife capable of handling nearly any type of input and output. To illustrate this, the following command is used in the Protomaps documentation to turn a US Census shapefile into GeoJSON:

ogr2ogr -t_srs EPSG:4326 cb_2018_us_zcta510_500k.json cb_2018_us_zcta510_500k.shp

If you think you know what's going on in that command, you may be ready for GDAL - otherwise, I suggest starting with GeoPandas.

2. Convert to PMTiles Format

Download and install tippecanoe (v2.17 or later) following the instructions in the GitHub repository.

Note: tippecanoe is only compatible with Unix-based systems. If you are using Windows, you can use the Windows Subsystem for Linux (WSL) to run tippecanoe. You can also install and run the command in a Docker container such as osgeo/gdal.

To convert the file, run the following command:

tippecanoe -zg --output=docs/tiles/ski_areas_all.pmtiles --projection=EPSG:4326 data/example/ski_areas_all.geojson

tippecanoe is an extremely flexible tool with many options to adjust how the tiles are generated. For more information, see the tippecanoe documentation.

3. Add to Map

The map code is included at the bottom of docs/index.html. The following code is added to the map:

// Setup PMTiles protocol with your map instance
let protocol = new pmtiles.Protocol();
maplibregl.addProtocol("pmtiles", protocol.tile);

// Create a new map instance
const map = new maplibregl.Map({
    container: 'map', // container ID
    style: 'https://basemaps.cartocdn.com/gl/dark-matter-gl-style/style.json', // style URL, replace with your own style if necessary
    center: [0, 0], // starting position [lng, lat]
    zoom: 1 // starting zoom
});


// Example of adding a PMTiles source and layer to your map
map.on('load', function () {
    map.addSource('skiAreas', {
        'type': 'vector',
        'url': 'pmtiles://tiles/ski_areas_all.pmtiles'
    });
    map.addLayer({
        'id': 'skiAreasCircles',
        'type': 'circle',
        'source': 'skiAreas',
        'source-layer': 'ski_areas_all',
        'paint': {
            'circle-radius': 6,
            'circle-color': 'rgba(255,255,255,0.5)'
        }
    });
});

4. Deploy with GitHub Pages

To deploy the map, push the changes to the main branch and enable GitHub Pages in the repository settings (https://github.com/PhilipMathieu/interactive-web-map/settings/pages).

1. Under "Build and Deployment" choose "Deploy from a branch"
2. Select the main branch
3. Select the /docs folder
4. Click "Save"

The map will be available at https://philipmathieu.github.io/interactive-web-map/.