Regina,
Yep, I used ST_LongestLine to confirm my length calc. I didn't think my
PostGIS fu was good enough to create a Postgresql function to find the
width and construct a rotated bbox (maybe some day)...
Thanks!
Best Regards,
Brent Fraser
On 6/18/2012 11:28 AM, Paragon Corporation wrote:
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-boun...@postgis.refractions.net
[mailto:postgis-users-boun...@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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