DRAFT — under teacher review.

Analytical Tools Template — UCD, Context Diagram, and DFD

Hamilton College · Year 12 · 2026

When you update your analytical tools in C3-1 (Step 1), you need to reproduce a Use Case Diagram, a Context Diagram, and a Data Flow Diagram. Setting up the notation from scratch each time costs 15–20 minutes and introduces layout errors. This page explains what is in the pre-labelled Excalidraw template and how to use it.

What the template contains

The Excalidraw file (C03-Analytical-Tools.excalidraw) has three pre-built diagram skeletons on a single canvas, each with placeholder nodes labelled by notation role:

Diagram	Pre-built elements
Use Case Diagram (UCD)	System boundary box; actor stick figures (primary user, secondary user); labelled oval placeholders for use cases; `«include»` and `«extend»` relationship stubs
Context Diagram	Central process circle (labelled with your system name placeholder); external entity rectangles on each side; labelled data-flow arrows in and out
Data Flow Diagram (DFD)	Level 1 layout with process circles, data store open rectangles, external entity rectangles, and directional arrow stubs; numbered process placeholders

All three diagrams use the standard Yourdon–DeMarco notation that VCAA markers expect.

How to use it

Download the file — ask your teacher for C03-Analytical-Tools.excalidraw.
Open in Excalidraw — go to excalidraw.com and drag the file onto the canvas, or use the Open menu.
Replace placeholders — click each labelled placeholder and type your own system name, actor names, use cases, data stores, and process names.
Add or remove elements — copy a placeholder shape to add more use cases, or delete extras. Keep the notation style consistent (don't mix shapes between diagram types).
Export — when done, export as PNG or SVG to paste into your SRS document.

What to notice when you update

Coming back to these diagrams from C02, check:

New actors: has your scope change added a new type of user? Add them to the UCD.
New data flows: does your updated scope require new data in or out? Update the Context Diagram arrows.
New processes: does the DFD reflect how data now moves through the updated system?

The rubric at 7–8 band requires diagrams that accurately reflect your current SRS — not your C02 version. Change what has changed; don't just copy-paste from C02.

Notation quick reference

Use Case Diagram

Symbol	Meaning
Stick figure	Actor (a person or external system that interacts with yours)
Oval	Use case (a goal the actor achieves using the system)
Rectangle	System boundary (what is inside vs outside the scope)
`«include»` arrow	Use case A always includes use case B
`«extend»` arrow	Use case B optionally extends use case A

Context Diagram

Symbol	Meaning
Circle	The system (one only — this is a Level 0 DFD)
Rectangle	External entity (person, group, or system outside your scope)
Arrow with label	Data flow (label = what data moves, direction = which way)

Data Flow Diagram (Level 1)

Symbol	Meaning
Circle	Process (transforms data; numbered: 1.0, 2.0…)
Open rectangle	Data store (where data is held; labelled D1, D2…)
Rectangle	External entity (same as context diagram)
Arrow with label	Data flow