I've been looking for a straightforward answer to this question but can't seem to find one.
The Mapbox Vector Tile Specification states implies that vector tile coordinates are unitless -- they're just in "vector tile grid coordinates" broadly defined by the "extent" -- often 4096.
On the other hand, the Mapbox Style Specification says that properties like line-width are in units of pixels. For instance, at zoom level 20 a minor road may be styled to have a line width of 30px.
To ensure consistent rendering between implementations, I would expect this would mean that a vector tile must have a defined conversion between "vector tile coordinates" and screen pixels (assuming it's being rendered at its native zoom level). I've seen some mention of 256px and/or 512px per tile, but I would expect this to be part of either the Vector Tile or Map Style specification. Changing a parameter like that would significantly affect the appearance of a map.
So: if I'm rendering a zoom-level-0 vector tile at exactly zoom level 0, how many pixels should the tile occupy on screen?
