<div dir="ltr"><span style="font-family:monospace">ST_Extent('SRID=4326;LINESTRING(-73 40, 53 27)'::geography::geometry) = </span><span style="font-family:monospace">BOX(-73 27,53 40)<br></span><span style="font-family:monospace">ST_Extent(ST_Segmentize('SRID=4326;LINESTRING(-73 40, 53 27)'::geography,100)::geometry) = </span><span style="font-family:monospace">BOX(-73 27,53 56.2529232769426)<br><br><br>In planar geometry your assumption should be valid, though.</span></div><br><div class="gmail_quote"><div dir="ltr">сб, 12 нояб. 2016 г. в 14:12, Sandro Santilli <<a href="mailto:strk@kbt.io">strk@kbt.io</a>>:<br></div><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">Doing topology loading tests I found time is spent to update<br class="gmail_msg">
the bounding box of faces whenever their edges are split.<br class="gmail_msg">
Following the train of thougths I arrived at asking myself:<br class="gmail_msg">
<br class="gmail_msg">
Is it possible that adding vertices in a segment could ever change<br class="gmail_msg">
the segment bounding box ?<br class="gmail_msg">
<br class="gmail_msg">
My answer is NO.<br class="gmail_msg">
<br class="gmail_msg">
Could you please review and confirm ?<br class="gmail_msg">
<br class="gmail_msg">
If my answer is correct, not only we can speed up topology loading,<br class="gmail_msg">
but also (for example) the ST_Segmentize function, which is currently<br class="gmail_msg">
*dropping* a cached BBOX value to be on the safe side (ie: to not<br class="gmail_msg">
answer that question).<br class="gmail_msg">
<br class="gmail_msg">
Math proofs welcome :)<br class="gmail_msg">
<br class="gmail_msg">
--strk;<br class="gmail_msg">
_______________________________________________<br class="gmail_msg">
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<a href="mailto:postgis-devel@lists.osgeo.org" class="gmail_msg" target="_blank">postgis-devel@lists.osgeo.org</a><br class="gmail_msg">
<a href="http://lists.osgeo.org/mailman/listinfo/postgis-devel" rel="noreferrer" class="gmail_msg" target="_blank">http://lists.osgeo.org/mailman/listinfo/postgis-devel</a></blockquote></div>