open-vector-tile

About

A Modified TypeScript implementation of the Mapbox Vector Tile library. It is backwards compatible but offers a lot of new features and improvements including (but not limited to):

Proper module treeshake.
Pre-Tessellated & Indexed geometries to quickly ship data to the renderer.
Support for 3D geometries.
Support for M-Values for each geometry point (used by lines and polygons).
- M-Values are stored as "Shapes" which reuses objects only needing to do lookups on values.
Column encoding of data to make it more compact. Better gzip and brotli compression.
Support nested objects in properties.

Inspiration

A very talented Markus Tremmel came up with the idea of migrating away from a row based approach to a column based approach with his COVTiles. I wanted to test the idea of simplifying his approach and see if it was worth the effort. Once I saw I got better results post compression I decided to finish this project.

Install

#bun
bun add open-vector-tile
# pnpm
pnpm add open-vector-tile
# yarn
yarn add open-vector-tile
# npm
npm install open-vector-tile

# cargo
cargo install ovtile

Example use

const fs = from 'fs'
import { VectorTile } from 'open-vector-tile'

// assume you can read (.pbf | .mvt | .ovt)
const fixture = fs.readFileSync('./x-y-z.vector.pbf')
// load the protobuf parsing it directly
const tile = new VectorTile(fixture)

console.log(tile)

// example layer
const { landuse } = tile.layers

// grab the first feature
console.log(landuse.feature(0))
console.log(landuse.feature(0).loadGeometry())

Development

Requirements

You need the tool tarpaulin to generate the coverage report. Install it using the following command:

cargo install cargo-tarpaulin

The bacon coverage tool is used to generate the coverage report. To utilize the pycobertura package for a prettier coverage report, install it using the following command:

pip install pycobertura

Running Tests

To run the tests, use the following command:

# TYPESCRIPT
## basic test
bun run test
## live testing
bun run test:dev

# RUST
## basic test
cargo test
# bacon
bacon test

Generating Coverage Report

To generate the coverage report, use the following command:

cargo tarpaulin
# bacon
bacon coverage # or type `l` inside the tool

open-vector-tile 0.1.0