[postgis-users] Minimum Bounding Rectangle

[Brent Fraser]

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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