An Sequence Diagram is on the the types of Interaction Diagram used to understand complex systems.
We also have a "activity" lifecycle diagram which shows clearly the states which a wallet can be in during its life.
Both "activity" and "sequence" diagrams are part of the UML software specifiction system. We also have a "class" diagram for troggle. That page also defines the "essential", "specification" and "implementation" levels at which troggle is designed and maintained.
This diagram was created online using the free software at www.websequencediagrams.com/.
You can edit your own version to revise this when it becomes outdated.
This is the entire source code that generates the diagram:
title Wallet Process Sequence
Survex file-->Survex file: copy empty svx template
note over Wallet: Put original notes into plastic wallet]
loop type survey points for each passage
Wallet->+Survex file: create svx file
Survex file->+Wallet: scan printed svx
end
Wallet-->Wallet: trace over printed svx
Wallet->+Drawing file: create .th or .xml file
Wallet-->Wallet: fix contents.json
# mode online https://www.websequencediagrams.com/
note over Wallet: in expofiles/surveyscans/
note over Drawing file: in :drawings: repo
note over Survex file: in :loser: repo
# Things to add on Drawing and Survex file sequences
# Survex file-->Survex file: create *include svx file (?)
# Drawing file-->Drawing file: re-edit to make whole survey (?)