[postgis-users] Rounding the angle of the polygon

[Witteveen, Eduard]

Stefan,

Thank you for your response, and you are right with your assumptions. 

I will have a look at the software suggested by you and test how it can do the job for me.

Thanks!

-----Oorspronkelijk bericht-----
Van: postgis-users-bounces at postgis.refractions.net
[mailto:postgis-users-bounces at postgis.refractions.net]Namens Stefan
Zweig
Verzonden: 18 January 2008 09:58 AM
Aan: PostGIS Users Discussion
Onderwerp: Re: [postgis-users] Rounding the angle of the polygon


Hi Christian,

i don't think that your task is a question that can be solved with typical GIS databases. At least postgis cannot. And I am quite sure that orcale & co. cannot either. Probably this would be a job to do with a adjustment package that allows to set angles as constraints. The Point is: to get one angle of the polygon correct you would have to move two other points which leads you into troubles with their enclosed angles.

I think taking the bounding box of the buildings will not help you, because most buildings have more than four corners, haven't they? Furthermore the bounding box would align all your building outline in north-south direction.

Have a look at adjustment /approximation software, just as http://www.xdesy.de/freeware/xdesy.html (german software, freeware) or similar products,


regards,

stefan


> -----Ursprüngliche Nachricht-----
> Von: PostGIS Users Discussion <postgis-users at postgis.refractions.net>
> Gesendet: 17.01.08 20:02:20
> An: PostGIS Users Discussion <postgis-users at postgis.refractions.net>
> Betreff: Re: [postgis-users] Rounding the angle of the polygon


> 
> Hi,
> 
> if I got your point of question correctly, why not calculating with the
> bounding box of relevant polygons?
> 
> Regards,
> Christian.
> 
> Am Donnerstag, den 17.01.2008, 09:32 +0100 schrieb Witteveen, Eduard:
> > Hello,
> > 
> > I have a large collection of polygons, where each polygon represents the shape of a building. The quality of the data is not perfect , but it can be used in a good way to give orientation in a map. However the problem is that not all the corners are 90 degrees, due to the quick-and-dirty way we gatherd the data. I want to change the corners, within a certain treshold (85-95), to become 90 degrees so it "looks" better on the orientation-map (and i think it will even improve the quality of my data, but im not sure of this).
> > 
> > Question: 
> > 	Is there a way to round the angle of the corners to 90 degrees of a polygon, where the corner is between 85 and 95 degrees? If this can't be done in (pl)sql, what would be "the way" to do this?
> > 
> > Furthermore, i've did searches on the mailinglist/google/oracle/.. but i couldnt find any leads except for the "degrees" function but im not sure how this method could help me
> > 
> > Eduard Witteveen
> > 
> > 
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DISCLAIMER:
Aan de informatie in deze e-mail en ieder aangehecht databestand kunnen geen rechten 
worden ontleend en de gemeente Aa en Hunze aanvaardt geen aansprakelijkheid voor 
schade als gevolg van onjuistheden en/of gedateerde informatie.

Als u niet de bedoelde ontvanger bent wilt u dan dit bericht en ieder aangehecht 
databestand verwijderen en de afzender hiervan via e-mail op de hoogte stellen.
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Deze mail is gescand met McAfee Webshield en bevat geen virussen.

Gemeente Aa en Hunze.