vt-pbf

What is vt-pbf?

The vt-pbf npm package is used for encoding vector tiles into Protocol Buffers (PBF) format. This is particularly useful in the context of geographic information systems (GIS) and mapping applications, where vector tiles are used to efficiently transmit map data.

What are vt-pbf's main functionalities?

Encoding GeoJSON to PBF

This feature allows you to encode a GeoJSON object into a PBF format. The code sample demonstrates how to convert a simple GeoJSON object into a PBF buffer.

const vtPbf = require('vt-pbf');
const geojson = { "type": "FeatureCollection", "features": [ { "type": "Feature", "geometry": { "type": "Point", "coordinates": [102.0, 0.5] }, "properties": { "prop0": "value0" } } ] };
const pbf = vtPbf.fromGeojsonVt({ 'layerName': geojson });
console.log(pbf);

Encoding multiple layers

This feature allows you to encode multiple GeoJSON layers into a single PBF. The code sample demonstrates how to convert two GeoJSON objects into a PBF buffer with multiple layers.

const vtPbf = require('vt-pbf');
const geojson1 = { "type": "FeatureCollection", "features": [ { "type": "Feature", "geometry": { "type": "Point", "coordinates": [102.0, 0.5] }, "properties": { "prop0": "value0" } } ] };
const geojson2 = { "type": "FeatureCollection", "features": [ { "type": "Feature", "geometry": { "type": "LineString", "coordinates": [ [102.0, 0.0], [103.0, 1.0] ] }, "properties": { "prop1": "value1" } } ] };
const pbf = vtPbf.fromGeojsonVt({ 'layer1': geojson1, 'layer2': geojson2 });
console.log(pbf);

Other packages similar to vt-pbf

geojson-vt

The geojson-vt package is used for slicing GeoJSON data into vector tiles on the fly in the browser or on the server. Unlike vt-pbf, which focuses on encoding data into PBF format, geojson-vt is more about creating vector tiles from GeoJSON data.

mapbox-gl

The mapbox-gl package is a powerful library for interactive, customizable vector maps on the web. While it includes functionality for handling vector tiles, it is a much broader library that includes rendering and interaction capabilities, unlike vt-pbf which is focused solely on encoding.

mvt

The mvt package is another library for working with Mapbox Vector Tiles (MVT). It provides tools for encoding and decoding MVT data. Compared to vt-pbf, mvt offers more comprehensive tools for both encoding and decoding vector tiles.

README

vt-pbf

Serialize Mapbox vector tiles to binary protobufs in javascript.

Usage

As far as I know, the two places you might get a JS representation of a vector tile are geojson-vt and vector-tile-js. These both use slightly different internal representations, so serializing each looks slightly different:

From vector-tile-js

var vtpbf = require('vt-pbf')
var VectorTile = require('@mapbox/vector-tile').VectorTile
var Protobuf = require('pbf')

var data = fs.readFileSync(__dirname + '/fixtures/rectangle-1.0.0.pbf')
var tile = new VectorTile(new Protobuf(data))
var orig = tile.layers['geojsonLayer'].feature(0).toGeoJSON(0, 0, 1)

var buff = vtpbf(tile)
fs.writeFileSync('my-tile.pbf', buff)

From geojson-vt

var vtpbf = require('vt-pbf')
var geojsonVt = require('geojson-vt')

var orig = JSON.parse(fs.readFileSync(__dirname + '/fixtures/rectangle.geojson'))
var tileindex = geojsonVt(orig)
var tile = tileindex.getTile(1, 0, 0)

// pass in an object mapping layername -> tile object
var buff = vtpbf.fromGeojsonVt({ 'geojsonLayer': tile })
fs.writeFileSync('my-tile.pbf', buff)

vtpbf.fromGeojsonVt takes two arguments:

• layerMap is an object where keys are layer names and values are a geojson-vt tile,
• options is an object (optional argument). There are 2 supported keys: version to define the version of the mvt spec used and extent to define the extent of the tile. version defaults to 1 and extent to 4096.