EPSG:4326 projection support

[ezze]

The specification states that

The global-mercator (aka Spherical Mercator) profile is assumed

Is there any reason why it's limited by only global-mercator profile while global-geodetic profile is also supported in TMS specification? Can global-geodetic profile be also added to this specification?

Our server application generates TMS tilesets in EPSG:4326 (global geodetic), and I was hoping that some MBTiles implementation such as node-mbtiles can be used to store all tiles of a tileset in a single file. Suprisignly, it can't.

Unfortunately, we can't reproject our tilesets to EPSG:3857 due to they cover the whole globe territory [-180;-90; 180; 90]. As the result, all MBTiles implementations (I guess) are useless in this case.

[pnorman]

Is there any reason why it's limited by only global-mercator profile while global-geodetic profile is also supported in TMS specification? Can global-geodetic profile be also added to this specification?

It's not really TMS, mbtiles is based on xyz.

[ezze]

Found similar closed issue but seems that there are no changes since that time. Related conversation doesn't clarify things for me.

While MBTiles is supposed to store tiles in a single file, does it matter which projection is used and how this projection is specified? Wouldn't it be enough to add some properties to metadata describing a number of tiles (x and y) on zero level?

[ezze]

@pnorman, thanks for clarification. Anyway, global-geodetic profile of TMS specification is another real example of xyz.