[gdal-dev] layer union returns a geometry collection

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[gdal-dev] layer union returns a geometry collection

Matthew Snape

Hello,

 

I am performing a union of two layers using OGR from Python…

 

layerA.Union(layerB, layerC,["PROMOTE_TO_MULTI=YES",])

 

This returns a layer composed of multipolygon’s  except for a single geometrycollection in the form…

 

GEOMETRYCOLLECTION (POINT (2610469.66 3325023.52),POLYGON ((2610439.3657 3325014.925899999……….

 

Is this expected behaviour, and if so what is it showing?

 

Any help appreciated

Thank you.

 

 

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Re: layer union returns a geometry collection

Ari Jolma-2

Matthew,

The documentation(1) says "The result layer contains features whose geometries represent areas that are either in the input layer, in the method layer, or in both.". I assume you a polygon in the input layer B which has a common singular point and common area with a polygon in layer C.

Ari

(1) http://gdal.org/classOGRLayer.html#adf0598c7dab1f4dbe3e2735e27450c9c


On 12.02.2018 11:58, Matthew Snape wrote:

Hello,

 

I am performing a union of two layers using OGR from Python…

 

layerA.Union(layerB, layerC,["PROMOTE_TO_MULTI=YES",])

 

This returns a layer composed of multipolygon’s  except for a single geometrycollection in the form…

 

GEOMETRYCOLLECTION (POINT (2610469.66 3325023.52),POLYGON ((2610439.3657 3325014.925899999……….

 

Is this expected behaviour, and if so what is it showing?

 

Any help appreciated

Thank you.

 

 

This e-mail message and any attached file is the property of the sender and is sent in confidence to the addressee only.

Internet communications are not secure and RPS is not responsible for their abuse by third parties, any alteration or corruption in transmission or for any loss or damage caused by a virus or by any other means.

RPS Group Plc, company number: 208 7786 (England). Registered office: 20 Western Avenue Milton Park Abingdon Oxfordshire OX14 4SH.

RPS Group Plc web link: http://www.rpsgroup.com



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Re: layer union returns a geometry collection

jratike80
In reply to this post by Matthew Snape
Matthew Snape wrote

> Hello,
>
> I am performing a union of two layers using OGR from Python...
>
> layerA.Union(layerB, layerC,["PROMOTE_TO_MULTI=YES",])
>
> This returns a layer composed of multipolygon's  except for a single
> geometrycollection in the form...
>
> GEOMETRYCOLLECTION (POINT (2610469.66 3325023.52),POLYGON ((2610439.3657
> 3325014.925899999..........
>
> Is this expected behaviour, and if so what is it showing?
>
> Any help appreciated
> Thank you.
>
> _______________________________________________
> gdal-dev mailing list

> gdal-dev@.osgeo

> https://lists.osgeo.org/mailman/listinfo/gdal-dev


Hi,

It would help a lot if you could find out and extract those source features
which make up that geometrycollection. Otherwise it is quite impossible to
answer.

-Jukka Rahkonen-



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