#315 Manage vector tiles servers

[Laurent Grenet]

More and more tile servers are now providing vector tiles (rather than raster tiles).
I'm not talking here of mapsforge maps, but servers that serve "elementary" tiles, but in .pbf format, like for example OpenTopoMaps that is able to serve either .png or .pbf tiles.
But more and more servers are serving ONLY vector .pbf tiles.

These tiles require specific software to be "transformed" in an image.
But I guess that open source tools able to manage these .pbf tiles and generate the corresponding png or jpg image are available.

It would then be great if MOBAC was able to download these vector tiles, and transform them "on the fly" in raster tiles, allowing to create "classic" atlases (with raster tiles) even when the original source is providing vector tiles.

[r_x]

To add such a new feature I need more information:

1. What tile size do those vector tiles have (if the tiles don't have a matching tile size procesing them in MOBAC won't work)?
2. What is the URL to get them (provide an example)

[Laurent Grenet]

Hi Robert,

I'm not sure it really makes sense to say the size of these vector tiles. Since they are vector tiles, it seems to me that it is the responsibility of rendering tool to define in which size they have to be rendered, no ?
If I'm OK, IMHO the best would to render them as 256x256 px tiles.
And if I'm wrong... I do not have any idea of the "native" tile size of such tiles, if they have such.

About the URL, there are several examples, but the most recent I have encountered is the vector tiles provided by OpenTopoMaps, and the URL is the following :

String getTileUrl( int zoom, int x, int y ) {
   return "https://opentopomap.org/otm/" + zoom + "/" + x + "/" + y + ".pbf";    
} 

And, as example, you'll find attached the tile around my home, both in .png (ie. providing from OpenTopoMaps "raster"), and in .pbf (ie. providing from OpenTopoMaps "vector"), ie 12/2123/1475 coordinates.