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I am trying to convert a polyline feature to a polygon by grouping using an attribute. I have around 5,000 distinct values and would expect to produce 5,000 polygons. But for some reason I'm getting 30,000 polygons.

I've been using the AreaBuilder.

I'm also seeing: 'Duplicate segment detected at location..'

 

Any suggestions? Thanks

Using the AreaBuilder I assume you have set the Group by to the distinctive attribute and the Input Ordered to No (unless your input is ordered by the attribute in the Group by).

Then only if you have multiple unattached polygons with the same Group by attribute can you get more than the 5000 areas for 5000 distinct values.


Using the AreaBuilder I assume you have set the Group by to the distinctive attribute and the Input Ordered to No (unless your input is ordered by the attribute in the Group by).

Then only if you have multiple unattached polygons with the same Group by attribute can you get more than the 5000 areas for 5000 distinct values.

I am having this same issue. I get many more polygons than expected even though I have set the GroupBy attribute as above. The AreaBuilder throws a number of errors e.g.

 

 

Duplicate segment detected at location (x=427001.990000 completeModel inconsistency found at location (x=401616.02660000045, y=284107.08659999998). Input data is not properly noded as specified in mapping file, continuing anywayModel inconsistency found at location (x=463352.38669999968, y=288460.45329999999). Input data is not properly noded as specified in mapping file, continuing anywayAreaBuilder_polygonizer(PolygonFactory): Now starting polygon construction...Model inconsistency found at location (x=387330.5700000003, y=203234.45000000001). Input data is not properly noded as specified in mapping file, continuing anywayAreaBuilder_polygonizer(PolygonFactory): PolygonFactory 98.9% completeAreaBuilder_polygonizer(PolygonFactory): PolygonFactory 100% completeAreaBuilder_polygonizer(PolygonFactory): Finished polygonizing group 5203 / 5203AreaBuilder_polygonizer(PolygonFactory): Formed 32607 polygonsAreaBuilder_polygonizer(PolygonFactory): 276458 line segment(s) did not closeAreaBuilder_polygonizer(PolygonFactory): Completed polygon formation on all groupsA point was encountered that was enclosed in more than one polygon.

 

 

Any suggestions?

 

 


Hi,

May be basic question, whether polylines are closed?

else better to use line closer and then try to build polygons


I suggest using the GeometryValidator before the AreaBuilder to detect and repair (if possible) any geometry errors. If you prefer, you can output geometry errors to a log or spatial layer for inspection and manual correction.

Depending on how your line data has been digitised, you may have multi-part line features which could benefit from going through the LineCombiner. I've had experience of something that looks like a single line, but which FME treats as an aggregate (i.e. multi-part feature) because the last node is actually in the middle of the line (due to being an output from the Aggregator).


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