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List:       postgis-users
Subject:    Re: [postgis-users] Possible for ST_Intersects to not include the perimeter?
From:       Ben Madin <ben () ausvet ! com ! au>
Date:       2015-01-23 5:31:00
Message-ID: CA+weYr1R5Qk6kLMjd7cDyYP+ucqJhZyicC_YWQhR0RCMp2=QRA () mail ! gmail ! com
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For two cents, a quick but inaccurate solution might be to shrink your
polygon slightly by using st_buffer() with a negative radius?

Ben

On 22 January 2015 at 16:50, toni hernández <toni@sigte.udg.edu> wrote:

> Joseph,
> 
> With St_Relate (http://postgis.net/docs/ST_Relate.html) we can get all
> kind of relations between geometries.
> You can get boundary intersections, interior intersections, interior
> intersections without boundary intersections.... all possibilities are
> supported.
> 
> St_Relate uses the DE-91M model to define this relations between
> geometries.
> To know more about DE-91M: http://en.wikipedia.org/wiki/DE-9IM
> 
> 
> 
> http://postgis.net/docs/using_postgis_dbmanagement.html#DE-9IM
> 
> 
> On 21/01/2015 22:22, Joseph Spenner wrote:
> 
> I have a polygon as an input, and I'm trying to find all polygons which
> share points, but not the perimiter points themselves.  Is this possible?
> 
> Real application:
> I have NWS polygons describing Thunderstorm Warnings, which are made up
> of counties within the state.  Some of those counties might be on the edge
> of the state.  I want to query my database to show me all Warnings which
> are in a supplied state.  However, if I query the *adjacent* state which
> borders the counties from the first state, I get those Warnings because
> they share the same parimeter points.
> 
> Is there a way to construct a query which will not return anything if
> the only points in common are the perimeter values themselves?
> 
> I tried a few variations on
> ST_Intersects/ST_Covers/ST_Contains/ST_Overlaps, supplying various AND/OR
> and TRUE/FALSE combinatins, but I can't seem to get the right combo to
> accomplish my task.
> 
> Any help would be great.
> 
> Thanks!
> 
> Regards,
> Joseph Spenner
> 
> 
> 
> 
> _______________________________________________
> postgis-users mailing \
> listpostgis-users@lists.osgeo.orghttp://lists.osgeo.org/cgi-bin/mailman/listinfo/postgis-users
>  
> 
> 
> _______________________________________________
> postgis-users mailing list
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> 



-- 

Ben Madin
BVMS PhD, MANZCVS

t : +61 8 6102 5535
m : +61 448 887 220
e : ben@ausvet.com.au

AusVet Animal Health Services
Western Australia

www.ausvet.com.au


[Attachment #5 (text/html)]

<div dir="ltr">For two cents, a quick but inaccurate solution might be to shrink your \
polygon slightly by using st_buffer() with a negative \
radius?<div><br></div><div>Ben</div></div><div class="gmail_extra"><br><div \
class="gmail_quote">On 22 January 2015 at 16:50, toni hernández <span \
dir="ltr">&lt;<a href="mailto:toni@sigte.udg.edu" \
target="_blank">toni@sigte.udg.edu</a>&gt;</span> wrote:<br><blockquote \
class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc \
solid;padding-left:1ex">  
    
  
  <div bgcolor="#FFFFFF" text="#000000">
    Joseph,<br>
    <br>
    With St_Relate (<a href="http://postgis.net/docs/ST_Relate.html" \
target="_blank">http://postgis.net/docs/ST_Relate.html</a>) we can get  all kind of \
relations between geometries. <br>  You can get boundary intersections, interior \
intersections, interior  intersections without boundary intersections.... all \
possibilities  are supported.<br>
    <br>
    St_Relate uses the DE-91M model to define this relations between
    geometries.<br>
    To know more about DE-91M: <a href="http://en.wikipedia.org/wiki/DE-9IM" \
target="_blank">http://en.wikipedia.org/wiki/DE-9IM</a><br>  <br>
    <br>
    <br>
    <a href="http://postgis.net/docs/using_postgis_dbmanagement.html#DE-9IM" \
target="_blank">http://postgis.net/docs/using_postgis_dbmanagement.html#DE-9IM</a><div><div \
class="h5"><br>  <br>
    <div>On 21/01/2015 22:22, Joseph Spenner
      wrote:<br>
    </div>
    </div></div><blockquote type="cite"><div><div class="h5">
      <div style="color:#000;background-color:#fff;font-family:garamond,new \
                york,times,serif;font-size:14px"><span>I have a polygon as an
          input, and I&#39;m trying to find all polygons which share points,
          but not the perimiter points themselves.   Is this possible?</span>
        <div dir="ltr"><br>
          <span></span></div>
        <div dir="ltr"><span>Real application:</span></div>
        <div dir="ltr"><span>   I have NWS polygons
            describing Thunderstorm Warnings, which are made up of
            counties within the state.   Some of those counties might be
            on the edge of the state.   I want to query my database to
            show me all Warnings which are in a supplied state.  
            However, if I query the <i>adjacent</i> state which borders
            the counties from the first state, I get those Warnings
            because they share the same parimeter points.</span></div>
        <div dir="ltr"><br>
          <span></span></div>
        <div dir="ltr"><span>Is there a way to
            construct a query which will not return anything if the only
            points in common are the perimeter values themselves?</span></div>
        <div dir="ltr"><br>
          <span></span></div>
        <div dir="ltr"><span>I tried a few
            variations on
            ST_Intersects/ST_Covers/ST_Contains/ST_Overlaps, supplying
            various AND/OR and TRUE/FALSE combinatins, but I can&#39;t seem
            to get the right combo to accomplish my task.</span></div>
        <div dir="ltr"><br>
          <span></span></div>
        <div dir="ltr"><span>Any help would be
            great.</span></div>
        <div dir="ltr"><br>
          <span></span></div>
        <div dir="ltr"><span>Thanks!</span></div>
        <div dir="ltr"><br>
          <span></span></div>
        <div dir="ltr"><span>Regards,</span></div>
        <div dir="ltr"><span>Joseph Spenner</span><br>
        </div>
        <div><br>
          <div>
            <br>
          </div>
        </div>
      </div>
      <br>
      <fieldset></fieldset>
      <br>
      </div></div><span class=""><pre>_______________________________________________
postgis-users mailing list
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target="_blank">postgis-users@lists.osgeo.org</a> <a \
href="http://lists.osgeo.org/cgi-bin/mailman/listinfo/postgis-users" \
target="_blank">http://lists.osgeo.org/cgi-bin/mailman/listinfo/postgis-users</a></pre>
  </span></blockquote>
    <br>
  </div>

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clear="all"><div><br></div>-- <br><div class="gmail_signature"><div dir="ltr"><br>Ben \
Madin<div>BVMS PhD, MANZCVS<br><br>t : +61 8 6102 5535<br>m : +61 448 887 220<br>e : \
<a href="mailto:ben@ausvet.com.au" \
target="_blank">ben@ausvet.com.au</a><br><br>AusVet Animal Health Services<br>Western \
Australia<br><br><a href="http://www.ausvet.com.au/" \
target="_blank">www.ausvet.com.au</a><br></div></div></div> </div>



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