Compare routes instead of straight-line guesses
See this course’s project requirements
Compare an existing and proposed service location in the supplied fictional four-zone town.
Keep your working files in your own notebook or software. Save a private description, checklist, and work link in My Proof.
What to include
- Define the decision and geographic layers with aggregate data.
- Plot a labeled coordinate grid and check units.
- Join attributes by zone ID and document missing-data checks.
- Calculate baseline and closure routes from the given network.
- Compare unique coverage and deliver a map, table and scoped memo.
Review and revise
Use these criteria to check your work and choose what to improve.
- Geographic meaning: layers, units and assumptions are explicit.
- Data quality: IDs and populations match without invented values.
- Calculation: route and unique coverage arithmetic is reproducible.
- Communication: the map supports a limited, accessible decision explanation.
Want more background?
The idea in everyday life
Straight-line proximity is different from an actual trip. Roads, crossings, schedules and permitted modes can change which service point is easiest to reach. The fictional network provides exact minute costs for a small hand calculation. These costs are exercise assumptions, not live travel estimates, accessible-route verification or advice about whether a route is safe.
A reachable route follows allowed connections and their costs.
One step at a time.
Use the sample or information you have permission to use. Keep your work as you go. You can pause between steps.
- 1
Label the undirected road links with fictional travel minutes: A-B=6, B-C=4, C-D=6 and D-A=8. Travel is allowed in either direction, and no diagonal link exists.
- 2
Calculate each zone’s shortest time to B. A takes six, B takes zero, C takes four, and D can use D-C-B for ten or D-A-B for fourteen.
- 3
Choose the smaller valid sum for D, recording the actual route as well as its time. A visually straight shortcut through the square is unavailable because the network contains no diagonal link.
- 4
Test a closure by removing B-C in a separate scenario. C must reach B through C-D-A-B, taking 6+8+6=20 minutes. Keep this scenario separate from the baseline.
- 5
Save baseline and closure route tables. Note that real routes would need current connections, mode, direction, time-of-day assumptions and relevant access conditions verified before using the result for travel.
See how it works.
Fictional route calculation: from D to service B, the northern path D-C-B costs 6+4=10 minutes. The southern path D-A-B costs 8+6=14, so the model selects ten. The geometric distance between D and B does not create a usable diagonal road. If B-C closes, C’s remaining path to B costs 6+8+6=20 minutes through D and A. The same point locations now produce very different access because network connectivity changed. The route table records both versions rather than mixing closure costs into the original baseline, preserving an auditable comparison.
Did you cover these?
- D to B is 10 via C in the baseline.
- No diagonal road is invented.
- C to B becomes 20 after B-C closes.
What to finish
Baseline and closure travel-time tables with route reasoning.
Watch for this
Calling straight-line distance a commute time or ignoring a missing connection.
How can I tell I understand it?
Show the path behind each calculated time.
Quick knowledge check
Answer all 3 questions. Get at least 2 right and the lesson completes automatically.
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Answer all 3 questions above and get at least 2 right. You can review the explanations and try again.
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Sources and further reading
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Source & access notes · checked 2026-09-10
Opened official CRS and projection tutorial. The exercise uses a labeled fictional Cartesian grid and never presents it as geographic coordinates.
Access: Free public reading; no account or certificate is required for this Life Starter course.
Reuse: Linked for reference. Examples, activities and assessments here are original; free access alone does not grant permission to reuse source text or branding.
Source & access notes · checked 2026-09-10
Opened official topographic map overview and product distinctions. Used for understanding map context and limits; no real route safety or current service claim is inferred.
Access: Free public reading; no account or certificate is required for this Life Starter course.
Reuse: Linked for reference. Examples, activities and assessments here are original; free access alone does not grant permission to reuse source text or branding.
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