From: Ryan Orth <ryan@seahat.com>
To: jeff@propertykey.com
Cc: pgsql-sql@postgresql.org
Subject: Re: nearest match
Date: Thu, 13 Mar 2003 11:22:21 -0600 (CST)
Message-ID: <10193.65.102.128.233.1047576141.squirrel@fordparts.com> (raw)
In-Reply-To: <3E709AF4.9050407@propertykey.com>
References: <10112.65.102.128.233.1047504752.squirrel@fordparts.com>
<3E709AF4.9050407@propertykey.com>
> Ryan wrote:
>> I'm doing some work with part diagrams and server-side image maps. I
>> want to store single point coordinates (x,y) for reference numbers in
>> a table looking like:
>>
>> reference_number text,
>> x int,
>> y int
>>
>> My question is: How can I find the *nearest* match of some clicked on
>> coordinates without specifying some arbitrary distance from the stored
>> point?
>
> How about something like this?
>
> select reference_number, '(50,50)'::point <-> point(x,y) as distance
> from my_table order by distance limit 1;
>
> With a reasonably small table, it should perform fairly well.
Hot damn! thats exactly what I needed. I imagine I would only be
comparing the distance of 50 points at any given time (about the max
number of reference numbers on any given image) so its mighty quick.
(184 points takes 1.80 msec to check)
I didn't even know about those geometric operators (I find new stuff every
day I swear). Are they SQL standard or postgres specific?
Ryan
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To: pgsql-sql@postgresql.org
Cc: ryan@seahat.com, jeff@propertykey.com
Subject: Re: nearest match
In-Reply-To: <10193.65.102.128.233.1047576141.squirrel@fordparts.com>
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