"Polygon feature must have at least 4 coordinates" ..rejecting REJECTING BELOW FEATURE:

is it a single polygonshapefile u read?

 

Then use a validator prior to deaggregating.

 

Or geometryfilter.

 

 

Or was there some processing done prior to deaggregating? Then check proces(ses).

 

 

On the other hand the aggregator just skips the offending tiem and continues.

you chack the log for their id and then inspect the file, see wich objects they are.

 

 

A polygon with 3 nodes would be, in fme, a line. Though any amount of vertices can be made inot a line and still be an area.. check for selfintersections.

 

 

 

This is an example of the error message.  I've tried outputting to SHP and TAB and get the same issue:

 

 

===========================================================================

 

Polygon feature must have at least 4 coordinates...rejecting

 

REJECTING BELOW FEATURE:

 

+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++

 

Feature Type: `LDN_SurfaceWaterFloodRiskOutlineByDepth_200yr_v4_dg_FINAL'

 

Attribute(string)           : `FldDepth' has value `>1.5m'

 

Attribute(string)           : `FldOutlnId' has value `GP10000024'

 

Attribute(string)           : `Notes' has value `West Drayton Model'

 

Attribute(string)           : `PK_ID' has value `20'

 

Attribute(string)           : `RP' has value `200'

 

Attribute(string)           : `ScenarioNm' has value `1 in 200 year'

 

Attribute(string)           : `Shape_Area' has value `4009.27598482'

 

Attribute(string)           : `Shape_Leng' has value `1511.34239698'

 

Attribute(string)           : `__wb_out_feat_type__' has value `LDN_SurfaceWaterFloodRiskOutlineByDepth_200yr_v4_dg_FINAL'

 

Attribute(string)           : `_hierarchy_id' has value `203750'

 

Attribute(string)           : `fme_feature_type' has value `LDN_SurfaceWaterFloodRiskOutlineByDepth_200yr_v4'

 

Attribute(string)           : `fme_geometry' has value `fme_aggregate'

 

Attribute(entangled: string): `fme_type' has value `fme_area'

 

          entangled to [SHAPE_GEOMETRY]

 

Attribute(string)           : `multi_writer_id' has value `0'

 

Coordinate System: `_BritishNatGrid_0'

 

Geometry Type: IFMEMultiArea

 

Number of Areas: 0

So it refusing to deaggregate aggregates?

 

I asusme u did inspect the shapefile by now?

 

 

a Multiarea with zero Area's....yous sure those are polygons and not lines?

 

On top it says:

 

LDN_SurfaceWaterFloodRiskOutlineByDepth_200yr_v4_dg_FINAL'":

 

suggesting lines...

 

 

Apart from this all, are you using deaggregator or not? Because that transformer deaggregates whatever type aggregate.

 

 

Wich proces outputs this error message?

I dont think the deaggreator is the problem.

 

The problem arrises when you try to write it to the shapefile, as this can hold only one geometrytype at a time.

 

 

After the deaggregator you need to capture the linear boundaries.

 

I assume the linear boundaries enclose the aggregated areas.

 

Use the geometryFilter to remove them or, if you need them as areas, use areabuilder on the boundaries.

I've tried to capture the linear boundaries by using GeometryFilter and then AreaBuilder, but I'm still getting the same warnings.

 

 

However, I've noticed that when I choose the Mode of "Preserve Hierarchy" in the Deaggregator I get the warnings, but using "Flatten One Level" I don't.  I don't understand the Help files explanation of the difference between the modes though - I just want to deaggregate the multi areas into separate areas.

I only get the warnings when I write to a Writer.  If I just use an Inspector I don't get the warnings.

 

 

If it is trying to deaggregate donuts (which do exist in the file), does that mean I should use one of the other modes?

 

 

There are over 100,000 features, so a bit hard to post..

FME aggregate geometry can be a tree structure.

 

e.g.

 

polygon1 and polygon2 belong to aggregate1.

 

aggregate1 and polygon3 belong to aggregate2.

 

 

In this example, aggregate2 is the topmost parent (root of the tree);

 

aggreate1 is a child of aggreate2 and also is parent of polygon1 and polygon2;

 

polygon1, polygon2 and polygon3 are leaves of the tree.

 

 

If you de-aggregate the topmost parent (aggregate2) with the Deaggregator (Mode: Preserve Hierarchy), output features will be:

 

- aggregate2: has no geometry, but has _hierarchy_child_id_list{}.

 

- aggregate1: has no geometry, but has _hierarchy_child_id_list{} and _hierarchy_parent_id.

 

- polygon1: has _hierarchy_parent_id.

 

- polygon2: has _hierarchy_parent_id. 

 

- polygon3: has _hierarchy_parant_id.

 

And, every feature has _hierarchy_id.

 

 

That is, the Deaggregator with the "Preserve Hierarchy" mode outputs every node of the tree structure. Every feature will have information of its parent and children, and parents may not have geometry.

 

 

You don't need to use the "Preserve Hierarchy" mode in many cases ;)

Addition.

 

"Flatten One Level": outputs aggregate1 (consists of polygon1 and polygon2) and polygon3

 

"Flatten All Levels": outputs polygon1, polygon2, and polygon3

 

in the example above.

Hi, thanks guys. 

 

 

Yes I believe that Preserving the Hierarchy is what is causing the warnings when writing to shapefile, as when I filter out features with hierarchy of 0, I don't get any warnings.

 

 

I tried the GeometryFilter but it kept outputting Areas only, perhaps I had the Deaggregator mode to a different setting the time I tried it.

 

 

Thanks again for your help.   I never understood the Hierarchy aspect properly before, but I believe I've got a grasp on it now.