Grid references and bearings — KCSE Geography

Grid references help in accurately locating points on a topographic map. A four-figure grid reference identifies a specific square on the map, while a six-figure grid reference pinpoints an exact location within that square.

To determine a four-figure grid reference:

1. Identify the grid square by locating the vertical (eastings) and horizontal (northings) lines.
2. Combine the numbers of the eastings and northings. For example, if the point is in the square between eastings 34 and 35, and northings 12 and 13, the four-figure grid reference is 3412.

For a six-figure grid reference:

1. Use the four-figure reference as a base.
2. Estimate the distance within the square to the nearest tenth of the eastings and northings.
3. If the point is approximately 0.3 east and 0.7 north within the square, the six-figure reference becomes 341273.

In summary:

• Four-figure: General location in a grid square.
• Six-figure: Precise location within that square.

To measure and state compass bearings between two points on a map, follow these steps:

1. Identify the two points: Locate the points you want to measure the bearing between.
2. Use a protractor: Place the protractor on the map so that the center is on the starting point.
3. Align the baseline: Ensure the baseline of the protractor is aligned with the north direction on the map.
4. Measure the angle: Look at the angle formed between the north line and the line connecting the two points. This angle is your bearing.
5. State the bearing: Always express the bearing in three figures, adding zeros if necessary. For example, a bearing of 45° should be stated as 045°.

Example: If Point A is located at 120° and Point B is at 300°, the bearing from A to B is measured as follows:

• Place the protractor at Point A.
• Measure the angle to Point B.
• If the angle is 300°, state it as 300°.

Remember, bearings are always measured clockwise from north.

To effectively draw a sketch map using grid references and bearings, follow these steps:

1. Understand Grid References: Grid references are composed of two numbers, indicating the eastings and northings. For example, a reference of (123, 456) means move 123 units east and 456 units north.

2. Identify Bearings: Bearings are angles measured clockwise from the north. For instance, a bearing of 045° indicates a direction northeast.

3. Sketching the Map:

   • Start by marking the grid reference on the map.
   • Use a protractor to measure the bearing from the grid reference point.
   • Draw lines to indicate the direction of features based on the bearings provided.
   • Label each feature clearly for easy identification.

4. Include Key Features: Ensure your sketch map includes essential features such as roads, rivers, or landmarks, as indicated by the grid references.

Remember, clarity and accuracy are key in sketch mapping. Practice drawing maps regularly to improve your skills and confidence.