Map Skills: Symbols, Keys, and Ordnance Survey Maps
Welcome to your guide on Ordnance Survey maps! Have you ever looked at a map and wondered what all the little pictures, letters, and numbers mean? Maps are like secret treasure guides to the world around us. In this chapter, you will learn how to read map symbols, work out heights using contours, find directions using an 8-point compass, and pinpoint any location using 4-figure and 6-figure grid references.
Don't worry if this seems tricky at first—once you know the simple rules, reading a map is just like cracking a fun code!
---1. What is an Ordnance Survey (OS) Map?
Ordnance Survey (OS) is Great Britain's national mapping agency. They create detailed, accurate maps of the entire country so walkers, drivers, builders, and geographers can explore without getting lost.
Understanding Map Scales
A real town is far too huge to draw on a piece of paper at its actual size! Maps shrink the real world down using a scale. In primary school, you will look at two main types of OS maps:
• \(1:25,000\) Scale (OS Explorer Maps): On this map, \(1\text{ unit}\) on paper represents \(25,000\text{ units}\) in real life. That means \(4\text{ cm}\) on the map equals \(1\text{ km}\) on the ground. These maps show lots of detail, including field boundaries and footpaths.
• \(1:50,000\) Scale (OS Landranger Maps): On this map, \(1\text{ unit}\) on paper represents \(50,000\text{ units}\) in real life. That means \(2\text{ cm}\) on the map equals \(1\text{ km}\) on the ground. These maps cover a larger area with slightly less tiny detail.
Watch Out for this Common Mistake: Many students think a \(1:50,000\) map is "larger" because \(50,000\) is a bigger number. In geography, a \(1:25,000\) map is called a larger-scale map because it shows features in bigger, closer detail!
Key Takeaway: Ordnance Survey maps shrink real-world distances down using scales like \(1:25,000\) (very detailed) and \(1:50,000\) (covers a bigger area).
---2. Map Symbols and the Key (Legend)
Real buildings and places are too big and complicated to draw fully on a map. If we tried to draw every brick and tree, the map would be a messy smudge! Instead, mapmakers use small, simple pictures and letters called symbols.
Every OS map has a panel called a Key (sometimes called a Legend). The key is your map dictionary—it tells you exactly what every symbol means.
Important KS2 OS Map Symbols to Remember
Here are the essential symbols you need to know:
• Churches: OS maps show three different types of church symbols so you can spot landmarks easily:
- Church with a tower: A cross with a small square on top.
- Church with a spire: A cross with a small circle on top.
- Church without a tower or spire: A simple cross on its own.
• Public House: Shown by the capital letters PH.
• Post Office: Shown by the letter P or the letters PO.
• Parking: A blue square with a white capital letter P.
• Viewpoint: A blue symbol shaped like an eye with small radiating lines coming out of it.
• Triangulation Pillar (Trig Point): A small blue triangle with a dot in the middle. These are real concrete pillars built on hills to help surveyors measure heights accurately.
Did you know? Map symbols represent real-world objects, but they are not exact photographs! They are drawn clearly so you can spot them instantly.
Key Takeaway: The key explains what symbols mean. Look closely at shapes and letters (like church towers, spires, and PH) to identify places.
---3. Contours and Land Height
How can a flat sheet of paper show high mountains and deep valleys? Ordnance Survey maps use contour lines.
What are Contours?
Contours are thin brown lines drawn across the map that join together points of equal height above sea level.
• Steep Land: When contour lines are packed very close together, it means the ground rises quickly—the slope is steep!
• Gentle Slopes or Flat Land: When contour lines are spaced far apart, the land rises gently. If there are no contour lines at all, the land is flat.
Common Mistake: Don't mix this up! Close lines mean a steep hill you would have to climb hard, not a flat field.
Key Takeaway: Brown contour lines show height. Close lines = steep slope; spread-out lines = gentle slope.
---4. Finding Direction: The 8-Point Compass
To navigate with a map, you need to know which direction you are facing. Maps are always drawn with North at the top.
The 8 Compass Points
The four main directions are the Cardinal Points: North (N), East (E), South (S), and West (W).
Between them are the four Intercardinal Points: North-East (NE), South-East (SE), South-West (SW), and North-West (NW).
Memory Trick for Clockwise Order (N, E, S, W):
"Naughty Elephants Squirt Water" or "Never Eat Shredded Wheat"
Key Takeaway: Use the 8 compass points (N, NE, E, SE, S, SW, W, NW) to describe which direction you are travelling.
---5. The National Grid and Grid References
OS maps are covered in a blue grid of squares called the National Grid.
Important Note: In geography, the National Grid is the system of map squares used across Great Britain—do not confuse it with the electrical power grid that delivers electricity to homes!
Eastings and Northings
• Eastings: The vertical lines that run up and down. Their numbers increase as you move towards the East (from left to right).
• Northings: The horizontal lines that run across. Their numbers increase as you move towards the North (from bottom to top).
The Golden Rule for Grid References
Always give the Easting first, and the Northing second!
Easy Memory Trick: "Along the corridor, then up the stairs!" (Go sideways along the Easting line first, then go upwards along the Northing line).
---6. Four-Figure and Six-Figure Grid References
Four-Figure Grid References (Finding a Whole Square)
A four-figure grid reference identifies an entire \(1\text{ km} \times 1\text{ km}\) grid square.
Step-by-Step Guide:
1. Find the target square on your map.
2. Look at the bottom-left corner of that square.
3. Read the 2-digit number of the vertical line (the Easting) on the left of the square.
4. Read the 2-digit number of the horizontal line (the Northing) at the bottom of the square.
5. Put them together! For example: Easting \(24\) and Northing \(63\) gives the four-figure reference \(2463\).
Six-Figure Grid References (Pinpointing an Exact Spot)
A four-figure reference finds a large \(1\text{ km} \times 1\text{ km}\) square, but what if you need to find a single building or a trig pillar? A six-figure grid reference pinpoints an exact location within \(100\text{ m}\) accuracy by dividing each grid square into tenths (\(0\) to \(9\)).
Step-by-Step Guide:
1. Find the four-figure square first (e.g., Easting \(24\) and Northing \(63\)).
2. Imagine the square is split into \(10\) equal slices from left to right. Count how many tenths along the square your symbol is (e.g., \(5\) tenths along). Add this number to your Easting: \(245\).
3. Now imagine the square is split into \(10\) equal slices from bottom to top. Count how many tenths up the square your symbol is (e.g., \(2\) tenths up). Add this number to your Northing: \(632\).
4. Combine them to get your 6-figure reference: \(245632\)!
Key Takeaway: 4-figure references identify a whole \(1\text{ km} \times 1\text{ km}\) square. 6-figure references pinpoint an exact location to \(100\text{ m}\). Always go along the corridor, then up the stairs!
---7. Quick Review: Summary Checklist
Check what you have learned:
• Ordnance Survey (OS): Great Britain's national mapping agency.
• Key/Legend: Shows what symbols (like PH for Public House or a blue triangle for a Trig Point) mean.
• Contours: Brown lines showing height. Closer lines = steeper ground.
• Compass Points: 8 points starting from North (N, NE, E, SE, S, SW, W, NW).
• Grid Lines: Eastings go along (vertical lines); Northings go up (horizontal lines).
• Grid References: 4 figures for a square, 6 figures for an exact spot—always give Eastings first, Northings second.