I have a lot of GeoJSON spatial data that I want to display on a leaflet map. Around 35,000 GeoJSON objects.
Because the amount of points can get very large, I wanted to use the geojson-vt library to tile my data on the client side.
Right now I have successfully tiled my data using the geojson-vt library:
var geoJson = {}; // Request to get data via API call not shown here
var tileOptions = {
maxZoom: 18,
tolerance: 5,
extent: 4096,
buffer: 64,
debug: 0,
indexMaxZoom: 0,
indexMaxPoints: 100000,
};
var tileIndex = geojsonvt(geoJson, tileOptions);
How do I integrate the vector tile data generated by geojson-vt to my Leaflet map?
Are there any recommended plugins or libraries that can help?
Geojson-vt's TileIndex.getTile()
returns a JSON version of the Mapbox vector tile spec:
I'm not aware of any library that can display this format. Indeed, Mapbox's own demo implements the visualisation at a fairly low level:
var tile = tileIndex.getTile(z, x, y);
console.timeEnd('getting tile z' + z + '-' + x + '-' + y);
if (!tile) {
console.log('tile empty');
zoomOut();
return;
}
// console.log('z%d-%d-%d: %d points of %d', z, x, y, tile.numSimplified, tile.numPoints);
// console.time('draw');
ctx.clearRect(0, 0, height, height);
var features = tile.features;
ctx.strokeStyle = 'red';
ctx.fillStyle = 'rgba(255,0,0,0.05)';
for (var i = 0; i < features.length; i++) {
var feature = features[i],
type = feature.type;
ctx.beginPath();
for (var j = 0; j < feature.geometry.length; j++) {
var geom = feature.geometry[j];
if (type === 1) {
ctx.arc(geom[0] * ratio + pad, geom[1] * ratio + pad, 2, 0, 2 * Math.PI, false);
continue;
}
for (var k = 0; k < geom.length; k++) {
var p = geom[k];
if (k) ctx.lineTo(p[0] * ratio + pad, p[1] * ratio + pad);
else ctx.moveTo(p[0] * ratio + pad, p[1] * ratio + pad);
}
}
if (type === 3 || type === 1) ctx.fill('evenodd');
ctx.stroke();
}
drawGrid();
You may be able to use some of their code to help you.
There are various references in the README and the related blog post to Mapbox-gl-js being "powered by" geojson-vt, but no explicit instructions on how to make that work. Perhaps the better approach is to simply use mapbox-gl-js GeoJSONSource.