[postgis-users] Minimum Bounding Rectangle

[Paragon Corporation]

It's on my todo.  well first step of my todo anyway.

http://trac.osgeo.org/postgis/ticket/1332

Brent -- thinking of your idea

Have you tried using ST_LongestLine?
http://www.postgis.org/documentation/manual-svn/ST_LongestLine.html

I'm hoping to get back to this ticket soon but tied up with other things.

Thanks,
Regina
http://www.postgis.us

 

> -----Original Message-----
> From: postgis-users-bounces at postgis.refractions.net 
> [mailto:postgis-users-bounces at postgis.refractions.net] On 
> Behalf Of Brent Fraser
> Sent: Monday, June 18, 2012 12:37 PM
> To: PostGIS Users Discussion
> Subject: Re: [postgis-users] Minimum Bounding Rectangle
> 
> Madison,
> 
>    I went looking a few months ago, but could find nothing.  
> I wrote some PHP to:
>      1. Find the length of the polygon (vertices farthest apart)
>      2. Find the width (based on vertices farthest from length line)
>      3. Build bounding box using length (with angle of the the length
> line) and the width
> 
> I'm still pondering the result when the input polygon is a square...
> 
> But there should really be something like a 
> "ST_ExtentRotated" or "ST_RotatedBBox"  function in PostGIS.
> 
> Best Regards,
> Brent Fraser
> 
> On 6/15/2012 2:03 PM, Madison Shaw wrote:
> > Hi,
> >
> > I was wondering if any one could possibly offer some advice.
> >
> > I am wanting to calculate the area for a minimum bounding rectangle 
> > for individual polygon features.  I know I can use st_envelope or 
> > st_extent along with st_area but this doesn't quite give me the 
> > results I am after.
> >
> > For example if the polygon was already a rectangle but was 
> orientated 
> > on an angle the bounding box area is much larger than the 
> area of the 
> > original rectangle, whereas I would like it to be the same 
> value.  I 
> > suppose what I am after is a convex hull but as a 
> rectangle. Is this 
> > possible?
> >
> > Any help is greatly appreciated.
> >
> > Cheers
> >
> > Madison
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> >
> 
> 
> 
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