Hi all,
I am currently using a Dissolver with Attribute Accumulation > Accumulation Mode set to ‘Use Attributes From One Feature’.
How does FME decide which feature's attributes are used? I assumed it would be the first one to enter the transformer, but I couldn't find anything on this in the documentation.
Kind regards,
Joep
It looks like it actually uses the attributes from the last feature. Probably because it is the easiest in terms of memory.
It looks like it actually uses the attributes from the last feature. Probably because it is the easiest in terms of memory.
Oh really? My workspace seems to use the first feature:
When changing the Sorter's Order to Descending, the _count attribute of the dissolved feature is 1.
It looks like it depends on your version.
Comparing 2024.1 and 2021.2
2024.1 takes the first, where as 2021.2 takes the last
Similarly, I have had different FME versions behave differently for whether first/last feature for Transformers that have this kind of Attribute merging handling.
Earlier versions of FME Eg. 2018 I had to make sure it was the last feature, whereas when upgraded to FM2021 had to go around to all my Sorters that where in Descending Order to get the first feature to enter the Transformer Last, and reverse them all back the other way since in later versions it seemed that the First Feature entering the Transformer now got used for the Attribute values.
How interesting. When birgit posted their reply I figured this had something to do with versions. Thanks everyone for the insights.
This seems like something Safe would want to put in the documentation of transformers with Attribute Accumulation parameters.