[stevage]

>The spec refers to 4096 tile sizes, but MapLibre seems to use 512 pixels,

I think OP is maybe confusing two different things. The 4096 is, IIRC, not "pixels" but rather "units of precision". They are saying that within a vector tile, the far left is 0, the far right is 4095, with 4096 discrete distance values between.

The 512 is about the portion of the map that is occupied by a vector tile, in "pixels". So if you have a vector tile with 4096 units of precision crammed into 512 pixels, that means you actually get a bit of sub-pixel precision, which is really helpful when you overzoom - you can stretch that same vector tile out over to a bigger and bigger area as you zoom in.

This matters because generally you generate vector tiles to some finite depth (eg, zoom 13) but then you want to be able to display them through to say zoom 17, which means the tile is going to be stretched 4 more zoom depths, so 2^4 (16) times wider/higher.

[ajd555]

Ah, I was missing that bit of information, and it explains why I was seeing these two values. Thank you stevage, I'll update the post with this info and cite you.

[stevage]

Vector tiles are super un-intuitive. They took me a very long time to get my head around, and I still feel shakey on some of the details.

FYI you might enjoy this talk I gave a few years back: https://www.youtube.com/watch?v=Zuo80hZYA1k

[ajd555]

Thank you - I will watch that with my coffee. I also realize this means I set the extent to 512 in the mvt file - that means I won't benefit from that subpixel precision you mentioned - I'll update the code and test it out