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Hi Everyone,

 

 

I'm finding that artifacts are being introduced in polygons created using a dissolver then aggregator.

 

 

Here's the boundary I can get with the ArcGIS dissolve tool:

 

 

 

 

However, using an FME dissolver > aggregator, basing the grouping on the same fields, I get artifacts introduced at the borders of the input polygons:

 

 

 

A closer look at the polygons during an edit session:

 

 

 

We're not sure how these are getting created as our polygons have gone through the ArcGIS topology tools, and do not have gaps.

 

 

Any guidance appreciated!

 

 

Thank you!!!

 

 

-mb

 

 
Hi,

 

 

ArcGIS applies a tolerance automatically when performing geometric operations.

 

FME generally manipulates geometries with full precision of floating point number.

 

I guess that's why you found the difference.

 

 

To resolve the slight gaps, try using the Snapper (Group By: <the same grouping fields>, Snapping Type: Segment Snapping) before dissolving.

 

 

Takashi
Looking forward to the day FME gets a workspace-wide setting for precision/tolerance that is automatically applied for all geometric operations!

 

 

David

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