Unit 16 · Positional Constraint Deduction

Six Towns on a Map — Compass Direction Deduction

Lesson 2 of 6

Lesson 2 of 6Positional Constraint Deduction

Six towns, five compass clues, one diagram. This question looks intimidating because of the number of towns and relationships, but the secret is to place the towns one clue at a time rather than trying to visualise all of them at once. The moment you anchor D at the bottom and build upward and outward, the map assembles itself in about 30 seconds.

Text-based compass direction mapping appears occasionally in OC TS, usually at the medium difficulty level. The question always gives exactly as many clues as needed to produce one unambiguous map. Students who draw as they read score reliably; students who try to hold the whole map in their head make errors on the east–west placements.

The examiner is checking whether you can translate each compass direction clue into a grid position, build a complete map by applying clues sequentially, and then correctly identify a compound direction (e.g. "northwest") from that map. The trap is confusing "due north" with "northwest" — the two are different.

Five or six towns are described with cardinal and ordinal direction relationships (north, northeast, west, etc.). After placing all towns on a mental or drawn grid, you identify the direction or relative position of a specific town from another. Compound directions (northwest, southeast, etc.) are tested because students often place B "due north" and then wrongly label it "northwest."

Best approach: Start with the town that has the most constraints and fix it in the centre of your grid. Build outward clue by clue, drawing a dot and letter for each town. Once the map is complete, draw a compass rose at the target town and read off which town falls in the asked direction. Never name a town "northwest" if it sits directly above (due north) or directly left (due west) of the target.

Question

There are six towns (A, B, C, D, E and F) in a region.

Town B is north of Town C and northeast of Town A. Town C is north of Town D and west of Town E. Town F is east of Town E.

Which town is northwest of Town D?

Select an answer to see the explanation.

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