Ordnance Survey Ireland (Leaving Cert Geography): Revision Notes

Ordnance Survey Ireland

Key Features of Ordnance Survey Maps

Scale and Detail

• OS maps used in exams are typically at a 1:50,000 scale.
• They show:
  • Physical features: Mountains, rivers, forests.
  • Human features: Buildings, roads, railways.

Grid References

• The map is divided into squares, each covering 1 km².
• Types of Grid References:
  • Four-figure references: Identify the square (e.g., O 12 34).
  • Six-figure references: Pinpoint a precise location (e.g., O 123 345).

Symbols

• OS maps use a key/legend to explain symbols for:
  • Natural features: Lakes, rivers, forests.
  • Man-made features: Schools, post offices, churches.

Contours and Altitude

• Contour lines show the height and shape of the land.
  • Interval: 10 metres.
  • Closer lines = Steeper slopes; Wider gaps = Gentle slopes.
• Spot heights provide exact elevations (e.g., 300 m).

Practical Applications of OS Maps

Analysing Relief and Landforms

• Identify physical features such as:
  • Mountains: Steep slopes, marked with close contour lines.
  • Valleys: U-shaped or V-shaped patterns.
  • Peneplains: Flat landscapes with few contour lines.
• Use OS maps to understand the relationship between landforms and human activity, e.g., settlements near rivers.

Examining Settlement Patterns

• Look for patterns in urban and rural areas:
  • Urban areas: Dense building symbols, and transport networks.
  • Rural areas: Dispersed houses, agricultural land.
• Consider the site and situation of settlements:
  • Why are towns located near rivers or at crossroads?

Transport Networks

• Roads and Railways:
  • Observe how towns are connected via primary and secondary routes.
• Key symbols to know:
  • National roads (thicker lines) vs. local roads (thin lines).

Tourism and Recreation

• OS maps highlight:
  • Hiking trails, forests, and scenic spots.
  • Historic sites: Castles, monastic settlements, and battlefields.

Key OS Map Symbols to Know

Things to Remember

1. Always identify the north arrow to orient yourself.
2. Read the map title—it gives you the location and context.
3. Link map features to the syllabus topics, e.g., settlements or rivers.