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O-Puzzle Series – November 26, 202

O-Puzzle Series – November 26, 2025


Today’s task is based on the map used in my book Planning Reliable Routes, the second book in the Confident Orienteering series. This same map is featured in one of the examples and on the cover of the book.

Task: Find 5 errors in the index contours.

Note: When completing the task, keep in mind that index contour “A” is correct.


 

Explanation and Answers:
An index contour is shown for every fifth contour line. Its function is very important — index contours (thicker lines) help us better understand the overall shape of the terrain and the height of slopes. 


1. The contour of the hill is at the same level as contour "A".
2. The contour of the depression is two intervals higher than the contours at level "B".
3. The contour of the depression is at the same level as the contours at level "B".
4. Same as case 3.
5. The contour of the hill is only two intervals above the contours at level "B".

***

Make the most of the off-season between 2025 and 2026 — review your navigation system if you're not satisfied with its current quality.
The Confident Orienteering book series -  a systematic approach to minimising errors - will definitely help you with that.

The most detailed analysis of navigation in orienteering:

Book 1: Fundamentals — Understand the causes of mistakes and develop strategies to reduce them.
Book 2: Planning Reliable Routes — Learn how to plan routes that account for a wide range of potential errors.

Aleksandr Alekseyonk, November 26, 2025. 

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