Nutritious Polygonal Meatball

    @2gis/geojson-vt
    TypeScript icon, indicating that this package has built-in type declarations

    3.2.3 • Public • Published

    geojson-vt — GeoJSON Vector Tiles

    Build Status

    A highly efficient JavaScript library for slicing GeoJSON data into vector tiles on the fly, primarily designed to enable rendering and interacting with large geospatial datasets on the browser side (without a server).

    Created to power GeoJSON in Mapbox GL JS, but can be useful in other visualization platforms like Leaflet, OpenLayers and d3, as well as Node.js server applications.

    Resulting tiles conform to the JSON equivalent of the vector tile specification. To make data rendering and interaction fast, the tiles are simplified, retaining the minimum level of detail appropriate for each zoom level (simplifying shapes, filtering out tiny polygons and polylines).

    Read more on how the library works on the Mapbox blog.

    There's a C++11 port: geojson-vt-cpp

    Demo

    Here's geojson-vt action in Mapbox GL JS, dynamically loading a 100Mb US zip codes GeoJSON with 5.4 million points:

    There's a convenient debug page to test out geojson-vt on different data. Just drag any GeoJSON on the page, watching the console.

    Usage

    // build an initial index of tiles
    var tileIndex = geojsonvt(geoJSON);
    
    // request a particular tile
    var features = tileIndex.getTile(z, x, y).features;
    
    // show an array of tile coordinates created so far
    console.log(tileIndex.tileCoords); // [{z: 0, x: 0, y: 0}, ...]

    Options

    You can fine-tune the results with an options object, although the defaults are sensible and work well for most use cases.

    var tileIndex = geojsonvt(data, {
    	maxZoom: 14,  // max zoom to preserve detail on; can't be higher than 24
    	tolerance: 3, // simplification tolerance (higher means simpler)
    	extent: 4096, // tile extent (both width and height)
    	buffer: 64,   // tile buffer on each side
    	debug: 0,     // logging level (0 to disable, 1 or 2)
    	lineMetrics: false, // whether to enable line metrics tracking for LineString/MultiLineString features
    	promoteId: null,    // name of a feature property to promote to feature.id. Cannot be used with `generateId`
    	generateId: false,  // whether to generate feature ids. Cannot be used with `promoteId`
    	indexMaxZoom: 5,       // max zoom in the initial tile index
    	indexMaxPoints: 100000 // max number of points per tile in the index
    });

    By default, tiles at zoom levels above indexMaxZoom are generated on the fly, but you can pre-generate all possible tiles for data by setting indexMaxZoom and maxZoom to the same value, setting indexMaxPoints to 0, and then accessing the resulting tile coordinates from the tileCoords property of tileIndex.

    The promoteId and generateId options ignore existing id values on the feature objects.

    GeoJSON-VT only operates on zoom levels up to 24.

    Install

    Install using NPM (npm install geojson-vt) or Yarn (yarn add geojson-vt), then:

    // import as a ES module
    import geojsonvt from 'geojson-vt';
    
    // or require in Node / Browserify
    const geojsonvt = require('geojson-vt');

    Or use a browser build directly:

    <script src="https://unpkg.com/geojson-vt@3.2.0/geojson-vt.js"></script>

    Install

    npm i @2gis/geojson-vt

    DownloadsWeekly Downloads

    491

    Version

    3.2.3

    License

    ISC

    Unpacked Size

    77.9 kB

    Total Files

    14

    Last publish

    Collaborators

    • kuznetcoff
    • artem.malko
    • trufi
    • lastw
    • andymost
    • itanka9
    • alxart
    • vitaliy.gis