If you want to extract features from a JSON array your transformer is the JSONFragmenter. You just need to point at the array location with a wildcard. In your case json["points"]

Thanks fgiron,

I can successfully execute the JSON Fragmenter using the advice above. The result is now I have several more records in my table which have effectively exploded the feature by the number of "points" it contains.

What I want to do now, is combine all of the "points" for each feature into a single string attribute, separated by a comma. So rather than having an exploded list, I have the original number of features, just with an attribute that lists all of the "points" it contains. How might I be able to do this?

Hi @bogus​ 

If you don't want to explode your "points" into different features it might actually be the JSONExtractor what you're looking for. Or just add an Aggregator after the JSONFragmenter to concatenate the attributes from the exploded features. Another alternative would be a ListBuilder, which lets you combine the attributes from the exploded feature into an attribute list in one feature.