<div dir="ltr">Sure, if you have suggestions for the content.  But we'll try to get to it soon anyway.</div><br><div class="gmail_quote"><div dir="ltr" class="gmail_attr">On Mon, Feb 1, 2021 at 10:38 PM Paolo Cavallini <<a href="mailto:cavallini@faunalia.it">cavallini@faunalia.it</a>> wrote:<br></div><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex">thanks a lot Martin for the clarification.<br>
should I open a ticket on the docs?<br>
cheers.<br>
<br>
Il 02/02/21 07:29, Martin Davis ha scritto:<br>
> Yes, ST_PointOnSurface computes a point which is guaranteed to lie<br>
> within a polygon.  This is not the case for the centroid, which may lie<br>
> outside a polygon (e.g the centroid of a C-shaped polygon lies outside<br>
> the polygon).<br>
> <br>
> The description of the algorithm in the GIS-SE question is essentially<br>
> correct.<br>
> <br>
> And yes, improving the documentation page would be good, as well as<br>
> providing some example diagrams.<br>
> <br>
> On Mon, Feb 1, 2021 at 10:15 PM Paolo Cavallini <<a href="mailto:cavallini@faunalia.it" target="_blank">cavallini@faunalia.it</a><br>
> <mailto:<a href="mailto:cavallini@faunalia.it" target="_blank">cavallini@faunalia.it</a>>> wrote:<br>
> <br>
>     Hi all,<br>
>     the description of the function is scanty. I always assumed it<br>
>     calculated the point within a polygon closest to the centorid, but I<br>
>     read it may not be so:<br>
>     <a href="https://gis.stackexchange.com/questions/76498/how-is-st-pointonsurface-calculated" rel="noreferrer" target="_blank">https://gis.stackexchange.com/questions/76498/how-is-st-pointonsurface-calculated</a><br>
>     <<a href="https://gis.stackexchange.com/questions/76498/how-is-st-pointonsurface-calculated" rel="noreferrer" target="_blank">https://gis.stackexchange.com/questions/76498/how-is-st-pointonsurface-calculated</a>><br>
>     Is this confirmed?<br>
>     In case, I suggest describing it in the manpage.<br>
>     Thanks for any clarification.<br>
>     Cheers.<br>
>     -- <br>
>     Paolo Cavallini<br>
>     <a href="http://www.faunalia.eu" rel="noreferrer" target="_blank">www.faunalia.eu</a> <<a href="http://www.faunalia.eu" rel="noreferrer" target="_blank">http://www.faunalia.eu</a>> - QGIS.org<br>
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<br>
-- <br>
Paolo Cavallini<br>
<a href="http://www.faunalia.eu" rel="noreferrer" target="_blank">www.faunalia.eu</a> - QGIS.org<br>
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</blockquote></div>