G46: Cartographic Skills
Atlas maps, OS maps, grid references, scale, distance, direction, gradient, contours, cross-sections, and sketch maps - the essential map skills for GCSE Geography.
🗺️ Atlas Maps
Definition: Atlas maps show large areas (continents, countries, regions) at small scales. They display general patterns such as climate zones, population density, biomes, and political boundaries.
Types of Atlas Maps
- Political maps: Show countries, borders, capital cities, and administrative regions
- Physical maps: Show relief (mountains, valleys), rivers, lakes, and coastlines using colour shading or contour lines
- Thematic maps: Show specific data patterns - choropleth (population density), isoline (temperature), dot (distribution of features)
- Topographic maps: Show both physical and human features with relief indicated
Exam Tip: When describing patterns on atlas maps, always use the language of distribution: "concentrated in...", "sparse in...", "follows the coastline...", "clusters around...", "increases from north to south..." Always use named places and compass directions.
📏 OS Maps and Scale
Key Fact: Ordnance Survey (OS) maps are the standard mapping used in GCSE Geography exams. The most common scales are 1:50,000 (Landranger - covers a larger area, less detail) and 1:25,000 (Explorer - covers a smaller area, more detail).
Understanding Scale
Scale = the relationship between distance on the map and distance on the ground.
1:25,000 means 1 cm on the map = 25,000 cm (250 m) on the ground.
1:50,000 means 1 cm on the map = 50,000 cm (500 m) on the ground.
Converting: To convert map distance to real distance: Real distance = Map distance × Scale
Example: 4 cm on a 1:25,000 map = 4 × 25,000 = 100,000 cm = 1,000 m = 1 km
| Map Scale | 1 cm represents | Common Use |
|---|---|---|
| 1:25,000 | 250 m | OS Explorer; walking; fieldwork; exam extracts |
| 1:50,000 | 500 m | OS Landranger; route planning; regional studies |
| 1:250,000 | 2.5 km | Regional road maps; atlas maps |
Measuring Distance
- Straight-line distance: Use a ruler to measure the distance on the map, then multiply by the scale. Alternatively, use the scale bar at the bottom of the map
- Curved distance (along a road/river): Use a piece of string or the edge of a sheet of paper. Mark the start point, then carefully follow the curve, marking each bend on the paper. Then measure the total length on the paper and convert using the scale
Example: Calculating Distance
On a 1:25,000 map, the distance between two points measured with a ruler is 6.4 cm. Real distance = 6.4 × 250 m = 1,600 m = 1.6 km. On a 1:50,000 map, the same real distance would measure only 3.2 cm on the map.
🔢 Grid References
4-Figure Grid References
Rule: "Along the corridor, then up the stairs" - always read the easting (horizontal number along the bottom) first, then the northing (vertical number up the side). A 4-figure grid reference identifies a 1 km × 1 km square.
How to give a 4-figure grid reference:
- Find the square containing the feature
- Read the easting (number along the bottom/left) of the left side of the square
- Read the northing (number up the side) of the bottom of the square
- Combine: easting then northing (e.g. 4728 = easting 47, northing 28)
6-Figure Grid References
Rule: A 6-figure grid reference identifies a point within a 1 km square to an accuracy of 100 m. You estimate the position within the square by dividing each side into tenths.
6-Figure Grid Reference Method:
1. Give the 4-figure reference for the square (e.g. 4728)
2. Estimate how many tenths across the feature is from the left edge of the square (0-9) - insert as the 3rd digit
3. Estimate how many tenths up the feature is from the bottom edge of the square (0-9) - insert as the 6th digit
4. Example: A church that is 3 tenths across and 7 tenths up in square 4728 → 473287
Example: 6-Figure Grid References
If a road junction is in the square bounded by easting 31 and northing 45, and it is approximately 5 tenths across from the left and 2 tenths up from the bottom, the 6-figure grid reference is 315452.
Common mistake: getting the order wrong. Always easting first (along), then northing (up). Think: you have to go along the corridor before you can go up the stairs.
🧭 Direction and Bearing
Compass Direction
The 8 cardinal and intercardinal directions: N, NE, E, SE, S, SW, W, NW. Always give direction FROM one place TO another.
Key Rule: "From A to B" means stand at A and face B - what compass direction are you facing? Common error: giving the direction from B to A instead of A to B.
Bearing
Bearing = the angle measured clockwise from north.
1. Draw a north line at your starting point
2. Draw a line from the starting point to the destination
3. Measure the angle clockwise from north to the destination line
4. Always give as a 3-figure number (e.g. 045°, not 45°)
Key bearings: North = 000°, East = 090°, South = 180°, West = 270°
Example: Calculating a Bearing
To find the bearing from a church at grid reference 475295 to a bridge at grid reference 482302: (1) Draw a north arrow at the church; (2) Draw a line to the bridge (the bridge is to the NE); (3) Use a protractor to measure clockwise from north to the line. The bearing is approximately 040°.
⛰️ Contours and Relief
Definition: Contour lines are lines on a map joining points of equal height above sea level. On OS maps, they are usually drawn at 10 metre vertical intervals (thicker lines at 50 m intervals). The closer the contour lines, the steeper the slope.
Interpreting Contour Patterns
| Landform | Contour Pattern | Description |
|---|---|---|
| Steep slope | Contour lines close together | Height increases rapidly over a short horizontal distance |
| Gentle slope | Contour lines far apart | Height increases gradually over a longer distance |
| Valley / V-shape | V-shaped contour lines pointing uphill (towards higher ground) | A river or stream flows along the valley floor; the V points to the source |
| Spur / Ridge | U-shaped contour lines pointing downhill (towards lower ground) | A finger of higher ground projecting from a hill; the U points to the lower end |
| Summit | Concentric rings getting smaller towards the centre | The highest point; often marked with a spot height or trig point |
| Depression | Concentric rings with hachures (small ticks) pointing inward | A hollow or crater lower than the surrounding land |
| Plateau | Closely spaced contours at the edge, wide spacing on top | Flat-topped elevated land with steep sides |
Key Rule: On a river, contour lines form a V pointing UPSTREAM (towards the source). The river flows DOWNSTREAM (away from the V point). If you see a V in the contours, the river flows out of the V - the V points to the source.
📐 Gradient and Cross-Sections
Calculating Gradient
Gradient = Vertical Interval (VI) ÷ Horizontal Equivalent (HE)
Or expressed as a ratio: Gradient = 1 : (HE ÷ VI)
Example: If the height rises 100 m over a horizontal distance of 500 m:
Gradient = 100/500 = 1/5 or 1:5
This means for every 5 units horizontally, the land rises 1 unit vertically.
Example: Calculating Gradient from an OS Map
A river flows from the 200 m contour to the 100 m contour over a map distance of 8 cm on a 1:25,000 map. Vertical Interval = 200 − 100 = 100 m. Horizontal Equivalent = 8 cm × 250 m/cm = 2,000 m. Gradient = 100/2000 = 1/20 or 1:20. This is a fairly gentle gradient, typical of a river's lower course.
Drawing Cross-Sections
Definition: A cross-section shows the shape of the land surface along a chosen line (transect). It converts contour information into a side-view profile of the landscape.
- Draw a straight line (transect) on the map between two points marked A-B
- Take a strip of paper and place it along the transect line
- Mark where each contour line crosses the transect, and note the height
- Draw horizontal and vertical axes on graph paper. Choose an appropriate vertical scale (often exaggerated - e.g. 1 cm = 50 m vertically vs 1 cm = 500 m horizontally)
- Plot each contour crossing as a point at the correct height
- Join the points with a smooth curve to show the land surface profile
- Label key features (river, summit, road, etc.) and annotate
Vertical Exaggeration: Cross-sections usually exaggerate the vertical scale to make relief features visible. If the horizontal scale is 1:25,000 and the vertical scale is 1:5,000, the vertical exaggeration is 25,000 ÷ 5,000 = 5 times. Always state the vertical exaggeration on your cross-section.
✏️ Sketch Maps
Definition: A sketch map is a simplified drawing of an area that shows key features without the detail of a proper map. It is used to illustrate a particular pattern, process, or relationship.
How to Draw a Sketch Map
- Draw the outline of the area (coastline, river, boundary) - don't try to be perfectly accurate, just capture the general shape
- Add key features only: main roads, rivers, settlements, land use areas
- Use labels and annotations to explain what is shown
- Add a title, north arrow, and approximate scale
- Use shading or colour to distinguish different areas (e.g. residential, industrial, green space)
- Keep it simple - don't include too much detail
Example: Urban Sketch Map
For a fieldwork study on urban land use, your sketch map might show: the CBD in the centre (shaded dark); inner city residential areas (medium shading); suburban areas (light shading); main roads as thick lines; the river as a wavy blue line; and arrows showing the direction of urban sprawl. Annotations explain: "CBD - highest land values", "Inner city - terraced housing, 1900-1930", "Suburbs - detached housing, post-1960".
❓ Practice Questions
Q1: Explain how to give a 6-figure grid reference.
Q2: On a 1:25,000 OS map, two points are 7.2 cm apart. What is the actual distance between them in kilometres?
Q3: Describe the contour pattern you would expect to see for (a) a steep slope, (b) a valley, (c) a summit.
Q4: A river drops 150 metres over a horizontal distance of 3 km. Calculate the gradient as a ratio.
Q5: Explain what vertical exaggeration is and why it is used in cross-sections.
Q6: What is a bearing and how is it different from a compass direction?
✅ Answers
- To give a 6-figure grid reference: (1) Identify the 1 km square the feature is in; (2) Read the easting (bottom-left number along the bottom); (3) Estimate how many tenths across the feature is from the left edge of the square (0-9) and insert as the 3rd digit; (4) Read the northing (bottom-left number up the side); (5) Estimate how many tenths up the feature is from the bottom edge (0-9) and insert as the 6th digit. Example: a feature 4 tenths across and 8 tenths up in square 4728 has the reference 474288.
- Actual distance = map distance × scale = 7.2 cm × 25,000 = 180,000 cm = 1,800 m = 1.8 km.
- (a) Steep slope: contour lines very close together, indicating height increases rapidly over a short distance. (b) Valley: V-shaped contour lines pointing uphill (towards higher ground), with the river flowing along the valley floor away from the point of the V. (c) Summit: concentric rings of contour lines getting smaller towards the centre, with the highest point in the middle, often marked with a spot height or trig point symbol.
- Gradient = VI ÷ HE = 150 m ÷ 3,000 m = 150/3000 = 1/20 or 1:20. This means for every 20 metres horizontally, the land rises 1 metre vertically.
- Vertical exaggeration is when the vertical scale of a cross-section is larger (shows more detail) than the horizontal scale, making slopes appear steeper than they really are. It is used because real landscapes often have gentle slopes that would appear almost flat if drawn at true scale. For example, if horizontal scale is 1:25,000 and vertical scale is 1:5,000, the vertical exaggeration is 5x. Always state the vertical exaggeration so the reader knows slopes appear steeper than reality.
- A bearing is a precise angle measured clockwise from north (0-360°), expressed as a 3-digit number (e.g. 045°, 270°). A compass direction is an approximate direction using cardinal and intercardinal points (N, NE, E, etc.). A bearing is more precise - "NE" could mean anything from 022° to 068°, while a bearing of 045° is exact.
🎯 Exam Tips
- Practise grid references - they appear on almost every geography exam
- Always read easting BEFORE northing ("along the corridor, up the stairs")
- When describing map features, use specific grid references to locate them
- For gradient calculations, always convert both distances to the same units first
- Contour interpretation is a key skill - practise identifying valleys, spurs, and summits
- When drawing cross-sections, label features and state vertical exaggeration
- Sketch maps should be simple with clear labels and annotations
- Use compass directions and bearings precisely - don't just say "over there"
📝 Exam Technique
Geography Exam Tips — Cartographic Skills:
1. For Cartographic Skills questions, always name specific case studies with factual detail
2. Use geographical terminology precisely (e.g. specific processes, not vague descriptions)
3. Consider social, economic and environmental perspectives in your evaluations
4. Support your points about Cartographic Skills with data, statistics or named examples
5. For 'assess' or 'evaluate' questions, reach a clear judgement supported by evidence
1. For Cartographic Skills questions, always name specific case studies with factual detail
2. Use geographical terminology precisely (e.g. specific processes, not vague descriptions)
3. Consider social, economic and environmental perspectives in your evaluations
4. Support your points about Cartographic Skills with data, statistics or named examples
5. For 'assess' or 'evaluate' questions, reach a clear judgement supported by evidence
⚠️ Common Errors
Watch Out!
Students often write vague answers without specific geographical evidence. Wrong: Writing generalised statements like 'it causes problems' Correct: Using specific data and named examples, e.g. 'the 2010 Haiti earthquake killed over 200,000 people due to poor building quality'
Students often confuse causes and effects. Wrong: Mixing up what caused the event with what resulted from it Correct: Clearly separate causes (why it happened) from effects (what happened as a result)
Students often describe rather than evaluate. Wrong: Listing strategies without assessing their effectiveness Correct: Weighing up strengths and weaknesses of each approach and reaching a supported judgement
✍️ Model Answer
Full-Mark Response
6 marks: Explain the key factors affecting cartographic skills.
Cartographic Skills involves multiple interconnected factors that geographers must understand. The key concepts include the processes that create and change cartographic skills, the impacts on both people and environment, and the strategies used to manage associated challenges. For a comprehensive answer, specific case study evidence should be used throughout, with named examples and data to support each point. Geographical terminology should be used precisely, and the interrelationship between physical and human factors should be demonstrated. Top-level responses evaluate the relative importance of different factors and consider how the situation varies between locations.
Mark scheme: 2 marks for identifying key factors, 2 marks for explaining processes with detail, 2 marks for using specific evidence
📊 AO Deep Dive
Assessment Objective Analysis
AO1 requires knowledge of the key facts and processes related to cartographic skills. AO2 demands understanding of how and why these processes operate, and their implications. AO3 asks you to analyse, evaluate and make judgements — this is where grade 9 answers stand out by weighing up competing perspectives and reaching supported conclusions. AO4 may involve interpreting maps, graphs or data related to this topic. To move from grade 5 to grade 9: use precise geographical terminology, support every point with specific case study evidence, and always evaluate rather than just describe.
📝 Exam Questions by Topic
🎬 Video Resources
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