Subset of a Set

Extracts a sub-set of a set. The selection uses the same action as the Filter, and is based on the parameter table. For the Set variable, the parameter table is stored in memory but the actual entries are stored on disk in a file or multiple files that are managed by ImageTank. When you take a sub-set, the new variable will reference the same files so nothing is written to disk. This means that the subset action is very fast even if logically the data set you are working with could be many gigabytes.