mapbox / mapbox/mbtiles-spec

EPSG:4326 projection support

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Description

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](http://wiki.osgeo.org/wiki/Tile_Map_Service_Specification#global-mercator) profile while [global-geodetic](http://wiki.osgeo.org/wiki/Tile_Map_Service_Specification#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](https://github.com/mapbox/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.

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First steps

  1. Read the whole issue, then the project's contributing guide.
  2. Comment on the issue to say you are picking it up — it saves two people doing the same work.
  3. Fork the repository and make your change on a branch.
  4. Open a pull request that references the issue number.

Research direction

Start by reading the MBTiles specification and the linked TMS global-mercator and global-geodetic profiles. Determine what specification changes would be needed to represent EPSG:4326 tilesets, and define completion as an explicit, consistent treatment of global-geodetic tiles alongside the existing profile.

Written by the indexing model from the issue text.

Assessment

Domain
documentation
Issue type
Feature
Difficulty
5/5
Estimated time
Over a week
Activity status
Stale
Clarity
Mostly clear
Newbie friendliness
30/100

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