Austria's government provides a lot of open data on its data.gv.at- Open Data Österreich portal. One of the treasures that can be found there are offline vector tiles for basemap.at Verwaltungsgrundkarte Österreich.

This readme will guide you through all steps required in order to host basemap.at vector tiles on your private server.

Since the tiles provided are contained in an ESRI Vector Tile Package (VTPK) and this container format cannot be served by open source tile servers we have written OpenVTPK in order to repackage the tiles into an MBTiles container.

Please read our detailed instructions on how to use OpenVTPK. After you have repackaged the vector tiles continue here.

The metadata has been updated and got a new timestamp. After a short analysis we could not find any improvement regarding the broken root.json style. It's worth noting that the basemap.at Offline vector Tiles are still labeled with the Beta tag.

We will assume that you followed the instructions provided by OpenVTPK and have your expanded basemap.at VTPK folder ready to use.

Since Docker is our best friend we are not going into a complicated setup procedure. We will use Klokan Technologies TileServer GL to serve the tiles and the corresponding styles.

The provided VTPK container also includes all resources required to style the vector tiles:

• fonts
• sprites
• styles

All the resources required are located in the p12/resources subfolder of your expanded VTPK container (see description above).

Let's create a folder that will become the root folder for TileServer GL (i.e. basemap) and copy the folders fonts, styles and sprites from the p12/resources folder. We do not need the infos folder.

Create an additional tiles folder and put the mbtiles file you want to serve here. Please follow the instructions above in order to repackage the basemap.at VTPK container which we will use in this example.

After that your folder structure should look like this:

basemap
  fonts
    Arial Regular
    Arial Bold
    Corbel Regular
    Corbel Bold
    Corbel Italic
    Corbel Bold Italic
    Tahoma Regular
  sprites
    sprite.png
      sprite.json
      sprite@2x.png
      sprite@2x.json
  styles
    root.json
  tiles
    Basemap_20190617.mbtiles

Unfortunately the root.json style shipped with the current version of basemap.at (as of October 28th 2019) contains a lot of errors:

mbgl: { class: 'ParseStyle',
  severity: 'WARNING',
  text: 'duplicate layer id STRASSENNETZ/BRUECKE/GIP_OUTSIDE_BAUWERK_L_BRÜCKE/112111/1' }
mbgl: { class: 'ParseStyle',
  severity: 'WARNING',
  text: 'duplicate layer id STRASSENNETZ/BRUECKE/GIP_OUTSIDE_BAUWERK_L_BRÜCKE/112111/0' }
mbgl: { class: 'ParseStyle',
  severity: 'WARNING',
  text: 'function value must specify stops' }
mbgl: { class: 'ParseStyle',
  severity: 'WARNING',
  text: 'function value must specify stops' }
mbgl: { class: 'ParseStyle',
  severity: 'WARNING',
  text: 'function value must specify stops' }
mbgl: { class: 'ParseStyle',
  severity: 'WARNING',
  text: 'function value must specify stops' }

(... many more lines ...) 

Please find a corrected version of the style file in our repository. The changes reflect

• renaming a duplicate style layer STRASSENNETZ/BRUECKE/GIP_OUTSIDE_BAUWERK_L_BRÜCKE/112111/0
• renaming a duplicate layer STRASSENNETZ/BRUECKE/GIP_OUTSIDE_BAUWERK_L_BRÜCKE/112111/1
• fixing

  mbgl: { class: 'ParseStyle',
  severity: 'WARNING',
  text: 'function value must specify stops' }
  

  by adding

  "stops": [
        [{"zoom": 17, "value": 0}, 0],
        [{"zoom": 18, "value": 0}, 0]
    ]
  

This file also contains modifications required to meet all path values we will use for the tile server:

    "sprite": "/sprite",
    "glyphs": "/{fontstack}/{range}.pbf",
    "sources": {
        "esri": {
            "type": "vector",
            "url": "/data/basemap.at.json"
        }
    }

Now we are ready to create a configuration file (config.js) for TileServer GL:

{
  "options": {
    "paths": {
      "root": "",
      "fonts": "fonts",
      "sprites": "sprites",
      "styles": "styles",
      "mbtiles": "tiles"
    }
  },
  "styles": {
    "basemap": {
      "style": "root.json",
      "serve_data": true
    }
  },
  "data": {
    "basemap.at": {
      "mbtiles": "Basemap_20190617.mbtiles"
    }
  },
  "settings": {
    "serve": {
      "vector": true,
      "raster": true,
      "services": true,
      "static": true
    },
    "raster": {
      "format": "PNG_256",
      "hidpi": 2,
      "maxsize": 2048
    }
  }
}

Open your console, change to the basemap folder we created and start TileServer GL:

docker run --rm -it -v $(pwd):/data -p 8080:80 klokantech/tileserver-gl
Starting Xvfb on display 99
xdpyinfo:  unable to open display ":99".
xdpyinfo:  unable to open display ":99".

Starting tileserver-gl v2.6.0
Using specified config file from config.json
Starting server
Listening at http://[::]:80/
Startup complete

Open your favorite browser and navigate to http://localhost:8080 (we have mapped TCP port 80 from within the docker container to port 8080 on our local machine):

Click on the Vector link on the dashboard in order to view your styled vector tiles. Depending on the correctness of the metadata in the VTPK file and the style rules (especially minzoom and maxzoom) your viewpoint may be out of scope and you will only see a white page. Please change the zoom level and the coordinates in the browser url accordingly.

The result is beautiful and available offline: