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

[Stephen Woodbridge]

On 11/12/2016 6:12 AM, Sandro Santilli wrote:
> 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 :)

What about curved geometries? like arc segments. Is the BBOX defined 
based on the true arc BBOX or the segmentized arc BBOX, if the later 
then changing the segmentation of an arc could in theory change hte BBOX.

-Steve


---
This email has been checked for viruses by Avast antivirus software.
https://www.avast.com/antivirus