Relief on OS Maps

How Relief is Represented on OS Maps

Contour Lines

• Definition: Thin brown lines that join points of equal elevation above sea level.
• Interval: On 1:50,000 OS maps, the contour interval is typically 10 meters.
• Key Characteristics:
  • Closely spaced contours = steep slopes.
  • Widely spaced contours = gentle slopes.
  • Circular contours indicate hills or mountains.

Spot Heights

• Definition: Exact elevation at a specific point, marked with a dot and a number (e.g., 350 m).
• Used to identify high points, such as summits.

Triangulation Pillars

• Represented by a small triangle with a spot height.
• Found at prominent hill or mountain peaks, used for surveying.

Shading

• Some maps use hill shading to indicate relief visually by simulating light and shadow.

Colouring

• Often used to show elevation ranges:
  • Dark green = lowland.
  • Light green/yellow = mid-elevation.
  • Brown = highland.

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Interpreting Relief Features

Hills and Mountains

• Circular or oval contour patterns with increasing elevation toward the center.

Valleys

• Contours form a "V" shape pointing upstream.
• Rivers or streams usually flow through the bottom of the valley.

Ridges

• Contours form long, narrow, elevated areas.

Plateaus

• Contours are widely spaced with few changes in elevation over a large area.

Cliffs

• Contours are extremely close together, often merging, indicating vertical or near-vertical slopes.

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Applications of Relief in Geography

Understanding Landforms

• Identify features such as hills, valleys, and plains.

Land Use and Settlement

• Analyze how relief influences activities like farming, forestry, and settlement patterns.
• Example: Flat areas are better suited for agriculture, while steep slopes are less accessible.

Navigation

• Plan routes based on terrain difficulty, avoiding steep slopes or following valleys.

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Key Tips for Interpreting Relief

• Always check the contour interval on the map's legend.
• Use spot heights and triangulation pillars for precise elevation data.
• Follow the "V" rule for valleys: the "V" points upstream.

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