identifing duplicate line features (with different draw directions0

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identifing duplicate line features (with different draw directions0

Basques, Bob (CI-StPaul)
I’m trying to remove all duplicated parcel edges from an exploded parcel dataset.  I have a set of 2 point line segments and I’ve been able to find the geom duplicates ok witha window partition, but the number was really low.  Upon examining the data more closely, I figured out that the majoirty of the duplicates are indeed the same line, but the end points are swapped around, so they appear in the window as different feature.

Anyone have a SQL chunk/function that I should look at to get to this matching of spatial location?  

Thanks

bobb




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Re: identifing duplicate line features (with different draw directions0

Richard Greenwood
Have you thought about using a topology? Seems like that's sort of what you're after.

On May 19, 2017 11:55 AM, "Basques, Bob (CI-StPaul)" <[hidden email]> wrote:
I’m trying to remove all duplicated parcel edges from an exploded parcel dataset.  I have a set of 2 point line segments and I’ve been able to find the geom duplicates ok witha window partition, but the number was really low.  Upon examining the data more closely, I figured out that the majoirty of the duplicates are indeed the same line, but the end points are swapped around, so they appear in the window as different feature.

Anyone have a SQL chunk/function that I should look at to get to this matching of spatial location?  

Thanks

bobb




"Be nice to people on your way up because you meet them on your way down." 
- Jimmy Durante




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Re: identifing duplicate line features (with different draw directions0

Tom van Tilburg-2
In reply to this post by Basques, Bob (CI-StPaul)
Yes, this should be done with the ST_Equals function: http://postgis.net/docs/ST_Equals.html
From the docs: "Returns true if the given geometries represent the same geometry. Directionality is ignored."

Best, 
  Tom

On Fri, May 19, 2017 at 7:55 PM, Basques, Bob (CI-StPaul) <[hidden email]> wrote:
I’m trying to remove all duplicated parcel edges from an exploded parcel dataset.  I have a set of 2 point line segments and I’ve been able to find the geom duplicates ok witha window partition, but the number was really low.  Upon examining the data more closely, I figured out that the majoirty of the duplicates are indeed the same line, but the end points are swapped around, so they appear in the window as different feature.

Anyone have a SQL chunk/function that I should look at to get to this matching of spatial location?  

Thanks

bobb




"Be nice to people on your way up because you meet them on your way down." 
- Jimmy Durante




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Re: identifing duplicate line features (with different draw directions0

Basques, Bob (CI-StPaul)
Tom,

Ok, that’s one I’ve never used before.  Sounds like it’s the right thing too.

Thanks

bobb


On May 24, 2017, at 2:43 AM, Tom van Tilburg <[hidden email]> wrote:

Yes, this should be done with the ST_Equals function: http://postgis.net/docs/ST_Equals.html
From the docs: "Returns true if the given geometries represent the same geometry. Directionality is ignored."

Best, 
  Tom

On Fri, May 19, 2017 at 7:55 PM, Basques, Bob (CI-StPaul) <[hidden email]> wrote:
I’m trying to remove all duplicated parcel edges from an exploded parcel dataset.  I have a set of 2 point line segments and I’ve been able to find the geom duplicates ok witha window partition, but the number was really low.  Upon examining the data more closely, I figured out that the majoirty of the duplicates are indeed the same line, but the end points are swapped around, so they appear in the window as different feature.

Anyone have a SQL chunk/function that I should look at to get to this matching of spatial location?  

Thanks

bobb




"Be nice to people on your way up because you meet them on your way down." 
- Jimmy Durante




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