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Identifying more than one polygon that lies within main dataset?

  • November 3, 2014
  • 5 replies
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Hi

 

 

I have have two datasets of polyonised data. 1. Field parcels 2. ineligible features that lie within field parcel polygons.. How can I identify if a field parcel polygon contains just one feature polygon or  two or more  feature polygons?

 

I'm relatively new to fm desktop and I'm wondering if there is a transformer that can help me with my issue?

 

 

 

thanks

Best answer by takashi

Hi,

 

 

I think the SpatialRelator helps you.

 

Send the Field parcels to the Requestor port, the ineligible features to the Supplier port of the transformer, and set a preferable spatial relation predicate to the "Tests to Perform" parameter. You can then get the number of related features as a new attribute (called "_related_candidates" by default).

 

Regarding definition of spatial relations, see here.

 

Spatial Relations Defined (http://docs.safe.com/fme/html/FME_Transformers/Default.htm#Transformers/spatialrelations.htm)

 

 

Takashi
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5 replies

takashi
Celebrity
  • Best Answer
  • November 4, 2014
Hi,

 

 

I think the SpatialRelator helps you.

 

Send the Field parcels to the Requestor port, the ineligible features to the Supplier port of the transformer, and set a preferable spatial relation predicate to the "Tests to Perform" parameter. You can then get the number of related features as a new attribute (called "_related_candidates" by default).

 

Regarding definition of spatial relations, see here.

 

Spatial Relations Defined (http://docs.safe.com/fme/html/FME_Transformers/Default.htm#Transformers/spatialrelations.htm)

 

 

Takashi

gio
Contributor
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  • Contributor
  • November 4, 2014
Expose format attribute "fme_feature_type"  (wich contains shapfile name, or layer name if autocad etc.).

 

After the test related_candidates>0 (eficiency) and subsequently >2 test for the "fme_feature_type" to idnetify wich intersects how often.

 

 

B.t.w. by using cardinality you can also test what kind of relation was detected.

 

 

Also you need to know that to some extent this transformer (SpatialRelator) is broken. It is or seems to be repaired in fme2015 beta, not in fme 2014 (yet?).

takashi
Celebrity
  • November 4, 2014
Gio, a few days ago, I got an information that the issue about cardinality calculation of the SpatialRelator has been fixed in FME 2015 beta build 15205. But the build is not available yet today (2014-11-04), I cannot confirm that.

 

Wait a moment!

takashi
Celebrity
  • November 7, 2014
FME 2015 beta build 15208 is now available. The issue has been fixed indeed.

gio
Contributor
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  • Contributor
  • November 7, 2014
yes, i have downloaded it.

 

 

Gonna try see if all spatial functions work corectly...