[postgis-devel] please review my assumption about segmentize and bbox

[Sandro Santilli]

Doing topology loading tests I found time is spent to update
the bounding box of faces whenever their edges are split.
Following the train of thougths I arrived at asking myself:

Is it possible that adding vertices in a segment could ever change
the segment bounding box ?

My answer is NO.

Could you please review and confirm ?

If my answer is correct, not only we can speed up topology loading,
but also (for example) the ST_Segmentize function, which is currently
*dropping* a cached BBOX value to be on the safe side (ie: to not
answer that question).

Math proofs welcome :)

--strk;