1. Nav B_4: Contours

2. Learning Intention: To enable you to understand and interpret contour lines on an OS map.

3. Success Criteria: By the end of this session everyone should be able to: Identify and state the purpose of contour lines on an OS map; Use contour lines to calculate the height of any given point. Some of you may be able to: Interpret the profile of a contoured feature and identify common geographical features from their contours/profiles.

4. Activities: 1.Presentation/Discussion: Hills of Braemar 2.Calculating Heights 3.Contour Interpretation

6. Contours – Key Points: Contour lines every 10m height change Bold contour line every 50m height change Closer together = steeper slope Farther apart = gentler slope Spot heights

7. Group Task: Calculating Heights Locate the features at the following Grid References and calculate their elevation above sea level to within 10m 1.Triangulation Pillar on summit of Ben MacDui (NN 988 989) 2.Loch Mhairc (NN 886 797) 3.Knoll (NN 861 697) 4.Hut (NO 173 810) 5.Monument (NO 157 928) 6.Track End (NO 036 863) 7.Head of burn (NO 011 677) 8.Waterfall (NO 064 777)

8. Answers: 1.1309m (!) 2.645m 3.550m 4.845m 5.330m 6.740m 7.535m 8.780m