I would like to know why the fme_feature_type attributes is removed after passing the lines features through areaBuilder transformer inserted inside a custom transformer.
Even more weird, just after areaBuilder, Im doing a FeatureMerger to restore all attributes to each feature as they were before going through some transformers, but only fme_feature_type is not passed.
Anybody may provide explanations on this?
Thank you,
-Max Demars
Best answer by gio
View original
the AreaBuilder will only include those attributes that are specified in the Group By-clause. This is because a resulting polygon could potentially contain a mixture of heterogenous values and FME has no automatic way of knowing which to preserve, except for those specified in the Group By.
If you need the individual values, specify a Polygon List Name (as per the documentation). This will the contain a list of all the attributes for each contributing polygons.
Regarding the FeatureMerger, I couldn't say, but in my experience it is often better to user e.g. an AttributeCopier to store these values in a different attribute than the internal ones used by FME (fme_* etc)
David
+3
So a group by on attributes wich are likely to be heterogenous, will not pass.
Group on homogenous attributes will pass.
Obviouly in your workspace the area is built up from different feature types.
U need to try and set some ID prior to the AB wich will identify the area's uniquely. (for instance insert a point an ID with a counter)
Also sometimes it possibel to do some logical operation on the contrbutors. (like it can only be build by grass feature type and water...etc.)
This logic also works on the merger: as only the suplier has the "fme_feature_type" passed, and the output "merged" are the area's built, it is logical that this attribute will not exit there. (it will exit trough referenced or no referenced ports)
Gio
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