Thanks for your answer.
I understand the general philosophy of JTS.
I think it's easy for me to return an other condition in the zero-width case.
Date: Wed, 11 Jun 2014 09:19:00 -0700
Subject: Re: [Jts-topo-suite-user] MinimumDiameter with POINT in input Geometry
From: [email protected]
To: [email protected]
CC: [email protected]
Answering "why not an exception" is the easy part... In JTS the general
philosophy is to prefer returning a representative geometry rather than
throwing an exception. This avoids disrupting chains of geometric operations
as much as possible.
However, there is another design goal, which is to return valid geometry
whenever possible. Obviously the MinimumDiameter is violating this principle
in the zero-width case. The original reason for making this choice is that it
was felt it was better to always return two points, even if they were
identical. That way handling code could know what to expect. It's fairly easy
to check for the zero-width condition, and take appropriate action to make the
output valid.
The alternative is to return a POINT when the output is zero-width.
What is the context in which you came across this issue? Would having a POINT
return work better?
On Wed, Jun 11, 2014 at 4:48 AM, Mireille Lecoeuvre
<[email protected]> wrote:
Hello,
I use MinimumDiameter class with getDiameter method.
When
I use this method with POINT in input Geometry the result is a
LINESTRING. But I find is strange to return a `LINESTRING` because the
result is a invalid Geometry.
Why the result is not an exception?
For example:
SELECT ST_MinimumDiameter('POINT(395 278)');
-- Answer: LINESTRING(395 278, 395 278)
Thanks for your help.
Mireille
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Find What Matters Most in Your Big Data with HPCC Systems
Open Source. Fast. Scalable. Simple. Ideal for Dirty Data.
Leverages Graph Analysis for Fast Processing & Easy Data Exploration
http://p.sf.net/sfu/hpccsystems
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