[postgis-users] polygon minimum width

Surya Tarigan surya.tarigan at yahoo.com
Sun Oct 18 19:39:54 PDT 2009


Simon,

Yes, I have solved the problem by merging left linestrings and also the right linestring aswell.

kind regards,

surya




________________________________
From: Simon Greener <simon at spatialdbadvisor.com>
To: PostGIS Users Discussion <postgis-users at postgis.refractions.net>
Sent: Thu, October 15, 2009 4:46:40 PM
Subject: Re: [postgis-users] polygon minimum width

Sury,

Sorry for the delay: you must have solved this by now.

My "test case" only had two linestrings as you didn't give us any real data to play with. Looking at your 5 row data result below seems to indicate that your river covers more than two rows. So, question to you, what is stored in each row? Which rows have the left data and which the right?

And if there are null geometries then you should do this:

select row_number() over (order by the_geom) as rin, the_geom
  from River r
  where r.Name = 'Barito'
    and r.the_geom is not null;

regards
Simon
On Wed, 14 Oct 2009 20:43:45 +1100, Surya Tarigan <surya.tarigan at yahoo.com> wrote:

> Dear Simon,
>
> the previous SQL ((select row_number() over (order by the_geom) as rin) gave good result, meanwhile the second SQL ( (select ctid as rin, the_geom) still return '0' min_width.  But I still need to check my river polyline, because both min and max give exactly  the  same result, which it should not..
>
> After I run :
>
> select row_number() over (order by the_geom) as rin, the_geom
>  from River r
>  where r.Name = 'Barito';
>  it gave result something like :
> rin, the_geom
> 1; -----(empty)---
> 2;-----(empty)---
> 3;010500000000........
> 4;010500000000..............
> 5;010500000.........
>  could it be caused by empty the_geom in rin 1 and 2?
>  kind regards,
>  sury
>
>
>
>


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