landuse=military on meta-tile boundaries

[pnorman]

At the intersection of four meta-tile boundaries there is a mismatch in hatching for z15 and below

Similar results on z16, z17, z18, but z14 is fine.

I have a theory as to why this is occurring, and how to fix it.

A z15 meta on orm is a z12 tile + 16 z12 pixel buffer. The buffer doesn't matter for what I think is wrong.

The areas covered by the metas are:

I believe polygon-clip: false may fix this. The description says

geometries are clipped to map bounds by default for best rendering performance. In some cases users may wish to disable this to avoid rendering artifacts."

cc @ToeBee

[gravitystorm]

Great investigation.

polygon-pattern-alignment: global is the preferred fix, along with ensuring the pattern is 256px repeating. If we can keep the clipping on, we get a (small) performance boost compared with switching it off.

[pnorman]

Does it need to be 256px repeating or just fit an integer number of times into 256px? (e.g. 128px, 64px, etc?)

[gravitystorm]

Integer number of times is fine.

[springmeyer]

yes polygon-pattern-alignment: global sounds like the right fix.