mbtiles

Node.js utilities and tilelive integration for the MBTiles format.

Installation

npm install node-mbtiles

var MBTiles = require('node-mbtiles');

API

Constructor

All MBTiles instances need to be constructed before any of the methods become available. NOTE: All methods described below assume you've taken this step.

let mbtiles=await new MBTiles('./path/to/file.mbtiles?mode={ro, rw, rwc}');

The mode query parameter is a opening flag of mbtiles. It is optional, default as rwc. Available flags are:

• ro: readonly mode, will throw error if the mbtiles is not existed.
• rw: read and write mode, will throw error if the mbtiles is not existed.
• rwc: read, write and create mode, will create a new mbtiles if the mbtiles is not existed.

Reading

async getTile(z, x, y)

Get an individual tile from the MBTiles table. This can be a raster or gzipped vector tile. Also returns headers that are important for serving over HTTP. 原来@mapbox的callback(null,tile,headers) 更改为 callback(null,{ tile:tile, headers:headers });

let tileInfo=await mbtiles.getTile(z, x, y);

async getInfo()

Get info of an MBTiles file, which is stored in the metadata table. Includes information like zoom levels, bounds, vector_layers, that were created during generation. This performs fallback queries if certain keys like bounds, minzoom, or maxzoom have not been provided.

let info=await mbtiles.getInfo();

async getGrid(z, x, y)

Get a UTFGrid tile from the MBTiles table. 原来@mapbox的callback(null,grid,headers) 更改为 callback(null,{ grid:grid, headers:headers });

let gridInfo=await mbtiles.getGrid(z, x, y);

Writing

async startWriting AND async stopWriting

In order to write a new (or currently existing) MBTiles file you need to "start" and "stop" writing. First, construct the MBTiles object.

await mbtiles.startWriting();
await mbtiles.stopWriting();

async putTile(z, x, y, buffer)

Add a new tile buffer to a specific ZXY. This can be a raster tile or a gzipped vector tile (we suggest using require('zlib') to gzip your tiles).

var zlib = require('zlib');

zlib.gzip(fs.readFileSync('./path/to/file.mvt'), async function(err, buffer) {
  await mbtiles.putTile(0, 0, 0, buffer);
});

async putInfo(data)

Put an information object into the metadata table. Any nested JSON will be stringified and stored in the "json" row of the metadata table. This will replace any matching key/value fields in the table.

var exampleInfo = {
  "name": "hello-world",
  "description":"the world in vector tiles",
  "format":"pbf",
  "version": 2,
  "minzoom": 0,
  "maxzoom": 4,
  "center": "0,0,1",
  "bounds": "-180.000000,-85.051129,180.000000,85.051129",
  "type": "overlay",
  "json": `{"vector_layers": [ { "id": "${layername}", "description": "", "minzoom": 0, "maxzoom": 4, "fields": {} } ] }`
};

await mbtiles.putInfo(exampleInfo);

async putGrid(z, x, y, grid)

Inserts a UTFGrid tile into the MBTiles store. Grids are in JSON format.

var fs = require('fs');
var grid = JSON.parse(fs.readFileSync('./path/to/grid.json', 'utf8'));
await mbtiles.putGrid(0, 0, 0, grid);

Hook up to tilelive

When working at scale, node-mbtiles is meant to be used within a Tilelive ecosystem. For example, you could set up an MBTiles file as a "source" and an S3 destination as a "sink" (using tilelive-s3). Assuming you have a system set up with an mbtiles:// protocol that points to a specific file and authorized to write to the s3 bucket:

var tilelive = require('@mapbox/tilelive');
var MBTiles = require('@mapbox/mbtiles');
var s3 = require('@mapbox/tilelive-s3');

s3.registerProtocols(tilelive);
MBTiles.registerProtocols(tilelive);

var sourceUri = 'mbtiles:///User/hello/path/to/file.mbtiles';
var sinkUri = 's3://my-bucket/tiles/{z}/{x}/{y}';

// load the mbtiles source
tilelive.load(sourceUri, function(err, src) {
  // load the s3 sink
  tilelive.load(sinkUri, function(err, dest) {

    var options = {}; // prepare options for tilelive copy
    options.listScheme = src.createZXYStream(); // create ZXY stream from mbtiles

    // now copy all tiles to the destination
    tilelive.copy(src, dst, options, function(err) {
      console.log('tiles are now on s3!');
    });
  });
});

Test

npm test