[postgis-devel] MVT API Q?

[Paul Ramsey]

So, one aspect of the MVT API that seems potentially problematic to me is
the "buffer" parameter in the ST_AsMVTGeom. Basically, the applies an
expansion to the "bbox", which is also provided to ST_AsMVTGeom. So far so
good.

But, the features fed into ST_AsMVTGeom will have been themselves selected
using a bbox. If that is the same bbox as fed into ST_AsMVTGeom (makes
sense) then it's possible that there are features that *should* be in the
tile (because they fall within the buffered area, but not within the bbox
itself) are *not* in the tile.

I'd expect a user to provide the same box to ST_AsMVTGeom as they use in
the WHERE clause, but that means potentially there will be features missing.

It's not a huge issue, but it will cause the buffering to be less
effective, and result in some poor renderings by client libraries in cases
of large symbols or line casings.

Or, I've misconstrued the whole thing, and need to be set right!

P.
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