Re: sdo_geom.sdo_area gives negative areas
Date: Fri, 9 May 2008 08:40:45 +0200
Message-ID: <4823f1ec$0$14353$e4fe514c@news.xs4all.nl>
"Jens Müller" <usenet-11-2007_at_tessarakt.de> schreef in bericht
news:68gehsF2sp00uU1_at_mid.individual.net...
> Hi,
>
> I used the sdo_geom.sdo_area function on some polygons in my database.
>
> The result is a negative number, the absolute value seems to be right.
>
> At a first glance, I did not find anything on this in the docs. Is this
> maybe due to a wrong direction (clockwise vs. counter-clockwise) of the
> points?
>
> If so, is this "bad" apart from the negative area values?
Yes, wrong direction is is bad. When your geometry is in the wrong direction, it is a 'hole' or a 'donut'. You will encounter problems calculating overlaps etc. About the negative area: I can't recall this has anything to do with the direction. What tolerance do you use?
Shakespeare Received on Fri May 09 2008 - 01:40:45 CDT