Subsystem

In STAN, I have already created three separate processes (arable land, grassland, and horticulture land) with all their flows and data entered. Can I convert these existing processes into subsystems (or sub‑processes) of a higher‑level ‘agricultural land’ process without having to re‑enter all the flow data?

Unfortunately, it is not possible in STAN to combine existing processes into a subsystem. You have to define the desired subsystem first, and then to model everything that is going on inside (sub-processes, additional internal flows).