Documentation on <#> and <-> operators

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Documentation on <#> and <-> operators

Matthew Baker
Hi all!

I'm trying to figure out what the <#> and <-> operators mean with PostGIS.

I have gotten them to work but I'm not exactly sure what is going on
under the hood... and also, for whatever reason, cannot seem to use
those operators as search terms for GIS.SE, Google, etc.

Thanks!

Matt Baker
Denver Public Schools
Denver, CO
[hidden email]


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Re: Documentation on <#> and <-> operators

Stephen V. Mather

Paul's posts are usually a helpful start:

https://carto.com/blog/lateral-joins


<#> is approximate (i.e. on bounding boxes) and was useful before PostgreSQL 9.5, as it could be used in a two step process to get the exact answer.


Really, now all you need is: <-> and a lateral join.


Cheers,

Best,

Steve


http://sig.cmparks.net/cmp-ms-90x122.png Stephen V. Mather
GIS Manager
(216) 635-3243 (Work)
clevelandmetroparks.com





From: postgis-users <[hidden email]> on behalf of Matthew Baker <[hidden email]>
Sent: Monday, July 3, 2017 11:29:15 AM
To: PostGIS Users Discussion
Subject: [postgis-users] Documentation on <#> and <-> operators
 
Hi all!

I'm trying to figure out what the <#> and <-> operators mean with PostGIS.

I have gotten them to work but I'm not exactly sure what is going on
under the hood... and also, for whatever reason, cannot seem to use
those operators as search terms for GIS.SE, Google, etc.

Thanks!

Matt Baker
Denver Public Schools
Denver, CO
[hidden email]


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[hidden email]
https://lists.osgeo.org/mailman/listinfo/postgis-users

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Re: Documentation on <#> and <-> operators

Hubel, Andreas
In reply to this post by Matthew Baker
Hello Matthew,

On 3. Jul 2017, at 17:29, Matthew Baker <[hidden email]> wrote:
> I'm trying to figure out what the <#> and <-> operators mean with PostGIS.

Here are the corresponding sections of the docs:
* http://postgis.net/docs//geometry_distance_knn.html
* http://postgis.net/docs//geometry_distance_box.html

I can recommend to download the docs as pdf or epub (e.g. from http://postgis.net/2017/07/01/postgis-2.3.3/ )
With the online/HTML version one often loses track of the context inside of the docs.

Regards,
Andreas

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