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List: postgis-users
Subject: Re: [postgis-users] OGC Simple Features Acces 1.21
From: Paul Ramsey <pramsey () cleverelephant ! ca>
Date: 2016-09-15 16:41:45
Message-ID: CACowWR2VeY3GgB=wYCJNkVTO0Wo3EP+v2_tT5HBLt1=e7uHprg () mail ! gmail ! com
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An inconsistency in an OGC specification!?!?!?
Could be. Fact remains, they do provide examples of mixed dimensional
inputs to the predicates, and they are the most confusing examples
imaginable, since what does it mean for polygons (or points) to "cross"? Or
for points to "overlap" vs "intersect".
If you're looking for precisely defined semantics of interaction, go with
the Relate() functions and DE9IM patterns, I'd recommend.
P
On Thu, Sep 15, 2016 at 6:15 AM, Ivan Santiago <isantiago@ogp.pr.gov> wrote:
> Hello all
>
>
> This is not directly related to Postgis but...
>
> I was reading the PDF document:
>
> <http://www.opengeospatial.org/standards/sfa>http://portal.opengeospatial.
> org/files/?artifact_id=25355
>
> <http://www.opengeospatial.org/standards/sfa>
> <http://portal.opengeospatial.org/files/?artifact_id=25355>
>
> Am I wrong or there is a contradiction in this?
>
> "The Overlaps relationship is defined for A/A, L/L and P/P situations.
> (p.38)
>
> ... so they must have the same dimension ...
>
>
> ... but in figure 12a, page 39 ...
>
> it shows an 'overlap' example using geometries of different dimensions
> (L/A)
>
> ???
> ------------------------------
> Iván Santiago
> GIS Specialist
> Information Technologies
> PR Office of Management and Budget
> 787.725.9420 x 2409
> http://gis.pr.gov/ <http://gis.pr.gov/>
>
> _______________________________________________
> postgis-users mailing list
> postgis-users@lists.osgeo.org
> http://lists.osgeo.org/mailman/listinfo/postgis-users
>
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<div dir="ltr">An inconsistency in an OGC specification!?!?!? <div>Could be. Fact \
remains, they do provide examples of mixed dimensional inputs to the predicates, and \
they are the most confusing examples imaginable, since what does it mean for polygons \
(or points) to "cross"? Or for points to "overlap" vs \
"intersect". </div><div>If you're looking for precisely defined \
semantics of interaction, go with the Relate() functions and DE9IM patterns, I'd \
recommend.</div><div>P</div></div><div class="gmail_extra"><br><div \
class="gmail_quote">On Thu, Sep 15, 2016 at 6:15 AM, Ivan Santiago <span \
dir="ltr"><<a href="mailto:isantiago@ogp.pr.gov" \
target="_blank">isantiago@ogp.pr.gov</a>></span> wrote:<br><blockquote \
class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc \
solid;padding-left:1ex">
<div dir="ltr">
<div style="font-size:12pt;color:#000000;background-color:#ffffff;font-family:'Lucida \
Console',Monaco,monospace"> <p>Hello all</p>
<p><br>
</p>
<p>This is not directly related to Postgis but...</p>
<p>I was reading the PDF document:</p>
<p><a href="http://www.opengeospatial.org/standards/sfa" target="_blank"></a><a \
href="http://portal.opengeospatial.org/files/?artifact_id=25355" \
target="_blank">http://portal.opengeospatial.<wbr>org/files/?artifact_id=25355</a></p>
<p><a href="http://www.opengeospatial.org/standards/sfa" target="_blank"></a><a \
href="http://portal.opengeospatial.org/files/?artifact_id=25355" target="_blank"><br> \
</a></p> <p>Am I wrong or there is a contradiction in this? <br>
</p>
<p><span>"The Overlaps relationship is defined for A/A, L/L and P/P situations. \
(p.38)</span></p> <p>... so they must have the same dimension ...<br>
</p>
<p><br>
</p>
<p>... but in figure 12a, page 39 ...</p>
<p> it shows an 'overlap' example using geometries of different dimensions \
(L/A)</p> <p>???<br>
</p>
<div>
<div style="font-size:12pt;color:#000000;background-color:#ffffff;font-family:Tw Cen \
MT"> <div style="font-size:13px;font-family:Tahoma">
<div style="font-size:13px;font-family:Tahoma">
<div style="font-size:13px;font-family:Tahoma">
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<div style="font-size:13px;font-family:Tahoma">
<div style="font-size:13px;font-family:Tahoma">
<hr>
<font style="font-family:'Lucida Console',Monaco,monospace">Iván \
Santiago<br> GIS Specialist<br>
Information Technologies<br>
PR Office of Management and Budget<br>
</font><font style="font-family:'Lucida Console',Monaco,monospace"><a \
href="tel:787.725.9420%C2%A0x%202409" value="+17877259420" \
target="_blank">787.725.9420 x 2409</a><br> </font><font \
style="font-family:'Lucida Console',Monaco,monospace"><a \
href="http://gis.pr.gov/" title="http://gis.pr.gov/ Ctrl+Cliquer ou appuyer pour \
suivre le lien" target="_blank">http://gis.pr.gov/</a></font><font face="Courier \
New"><a href="http://gis.pr.gov/" target="_blank"></a> </font></div>
</div>
</div>
</div>
</div>
</div>
</div>
</div>
</div>
</div>
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