Integrate GeoJSON-VT by MapBox into Cesium

[jor...@techmaven.net]

https://github.com/mapbox/geojson-vt

Slice large geojson files into vector tiles in the browser

( could add support to shapefiles and file geodatabases and other vector data and convert to geojson and then vector tiles - https://github.com/calvinmetcalf/shapefile-js   https://github.com/wavded/js-shapefile-to-geojson

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
    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)

    indexMaxZoom: 4,        // max zoom in the initial tile index
    indexMaxPoints: 100000, // max number of points per tile in the index
    solidChildren: false    // whether to include solid tile children 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.