flyingliang / mbtileserver

Basic Go server for mbtiles

mbtileserver

A simple Go-based server for map tiles stored in mbtiles format.

Requires Go 1.8.

It currently provides support for png, jpg, and pbf (vector tile) tilesets according to version 1.0 of the mbtiles specification. Tiles are served following the XYZ tile scheme, based on the Web Mercator coordinate reference system.

At the moment, UTF8 Grids are not yet supported.

In addition to tile-level access, it provides:

• TileJSON 2.1.0 endpoint for each tileset, with full metadata from the mbtiles file.
• a preview map for exploring each tileset.
• a minimal ArcGIS tile map service API (work in progress)

It uses golang/groupcache to provide caching of tiles for even faster performance.

We have been able to host a bunch of tilesets on an AWS t2.nano virtual machine without any issues.

Goals

• Provide a web tile API for map tiles stored in mbtiles format
• Be fast
• Run on small resource cloud hosted machines (limited memory & CPU)
• Be easy to install and operate

Installation

Currently, this project is not go get-able because static assets and templates are not downloaded via go get. We're working toward this.

In the meantime, clone this repository using your git tool of choice.

This uses Govendor tool, so dependencies ship with the repo for easier builds.

Dependencies:

• github.com/labstack/echo
• github.com/mattn/go-sqlite3
• github.com/spf13/cobra
• github.com/golang/groupcache
• github.com/Sirupsen/logrus

On Windows, it is necessary to install gcc in order to compile mattn/go-sqlite3.
MinGW or TDM-GCC should work fine.

Then build it:

go build .

This will create an executable called mbtileserver.

If you experience very slow builds each time, it may be that you need to first run

go build . -a

to make subsequent builds much faster.

Usage

From within the repository root:

$  ./mbtileserver --help
Serve tiles from mbtiles files

Usage:
  mbtileserver [flags]

Flags:
      --cachesize int   Size of cache in MB. (default 250)
  -c, --cert string     X.509 TLS certificate filename.  If present, will be used to enable SSL on the server.
  -d, --dir string      Directory containing mbtiles files. (default "./tilesets")
      --dsn string      Sentry DSN
  -k, --key string      TLS private key
  -p, --port int        Server port. (default 8000)
  -v, --verbose         Verbose logging

So hosting tiles is as easy as putting your mbtiles files in the tilesets directory and starting the server. Woo hoo!

You can have multiple directories in your tilesets directory; these will be converted into appropriate URLs:

mytiles/foo/bar/baz.mbtiles will be available at /services/foo/bar/baz.

When you want to remove, modify, or add new tilesets, simply restart the server process.

If a valid Sentry DSN is provided, warnings, errors, fatal errors, and panics will be reported to Sentry.

Specifications

• expects mbtiles files to follow version 1.0 of the mbtiles specification. Version 1.1 is preferred.
• implements TileJSON 2.1.0

Creating Tiles

You can create mbtiles files using a variety of tools. We have created tiles for use with mbtileserver using:

• TileMill (image tiles)
• tippecanoe (vector tiles)
• tpkutils (image tiles from ArcGIS tile packages)

Examples

TileJSON API for each tileset: http://localhost/services/states_outline

returns something like this;

{
  "bounds": [
    -179.23108,
    -14.601813,
    179.85968,
    71.441055
  ],
  "center": [
    0.314297,
    28.419622,
    1
  ],
  "credits": "US Census Bureau",
  "description": "States",
  "format": "png",
  "id": "states_outline",
  "legend": "[{\"elements\": [{\"label\": \"\", \"imageData\": \"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAABQAAAAUCAYAAACNiR0NAAAAAXNSR0IB2cksfwAAAAlwSFlzAAAOxAAADsQBlSsOGwAAAGFJREFUOI3tlDEOgEAIBClI5kF+w0fxwXvQdjZywcZEtDI31YaQgWrdPsYzAPFGJCmmEAhJGzCash0wSVE/HHnlKcDMfrPXYgmXcAl/JswK6lCrz89BdGVm1+qrH0bbWDgA3WwmgzD8ueEAAAAASUVORK5CYII=\"}], \"name\": \"tl_2015_us_state\"}]",
  "map": "http://localhost/services/states_outline/map",
  "maxzoom": 4,
  "minzoom": 0,
  "name": "states_outline",
  "scheme": "xyz",
  "tags": "states",
  "tilejson": "2.1.0",
  "tiles": [
    "http://localhost/services/states_outline/tiles/{z}/{x}/{y}.png"
  ],
  "type": "overlay",
  "version": "1.0.0"
}

It provides most elements of the metadata table in the mbtiles file.

XYZ tile endpoint for individual tiles: http://localhost/services/states_outline/tiles/{z}/{x}/{y}.png

If UTF-8 Grid data are present in the mbtiles file, they will be served up over the grid endpoint: http://localhost/services/states_outline/tiles/{z}/{x}/{y}.json

Grids are assumed to be gzip or zlib compressed in the mbtiles file. These grids are automatically spliced with any grid key/value data if such exists in the mbtiles file.

The map endpoint: http://localhost/services/states_outline/map

provides an interactive Leaflet map for image tiles, including a few helpful plugins like a legend (if compatible legend elements found in TileJSON) and a transparency slider. Vector tiles are previewed using Mapbox GL.

ArcGIS API

This project currently provides a minimal ArcGIS tiled map service API for tiles stored in an mbtiles file. This should be sufficient for use with online platforms such as Data Basin. Because the ArcGIS API relies on a number of properties that are not commonly available within an mbtiles file, so certain aspects are stubbed out with minimal information.

This API is not intended for use with more full-featured ArcGIS applications such as ArcGIS Desktop.

Live Examples

These are hosted on a free dyno by Heroku (thanks Heroku!), so there might be a small delay when you first access these.

• List of services
• TileJSON for a PNG based tileset generated using TileMill.
• Map Preview for a map preview of the above.
• ArcGIS Map Service

Roadmap

See the issues tagged to the 0.5 version for our near term features and improvements.

In short, we are planning to:

• make this project go get-able
• add tests and benchmarks
• get things production ready

Development

Development of the templates and static assets likely requires using node and npm. Install these tools in the normal way.

From the templates/static folder, run

$npm install

to pull in the static dependencies. These are referenced in the package.json file.

Then to build the minified version, run:

$gulp build

Modifying the go files requires re-running go build.