Measuring Distances on Maps
(a) Measuring along a straight line
The following are the appropriate steps to follow
- Mark the two end points on the map
- Join the two points with a straight light pencil line
- Place a piece of paper with a straight edge neatly on the map along the pencil line joining the two points.
- Mark exactly where each point touches the straight edge of the paper.
- If you have used a ruler, calculate the distance using the given scale.
Measuring along winding distance (irregular line)
Curved lines on maps include features like rivers, roads, railway line and boundaries. There are three methods used to measure irregular lines.
(a) Using the straight edge of paper.
- Place a piece of paper with its top left- hand corner at the starting point.
- Rotate the paper until it covers a short straight portion and mark it while holding it firmly.
- Move the paper until it lies along the next straight section of the line.
- Keep moving the paper until the whole distance has been measured. Mark the end point on the edge of the paper.
- Transfer the straight edge of paper along the linear scale reading off the distance.
(b) Using a thread
1. Get a thin non- elastic thread which is longer than the distance you wish to measure.
2. Mark one end of the thread in ink.
3. Place and hold the marked end of the point of the line on the map.
4. Then lay the thread along the winding distance until you reach the end of the line and mark this point on the thread.
5. Transfer the length of the thread and stretch it over the linear scale and read off the distance.
(c) Using a pair of dividers
- This is done by marking the entire length into short straight portions by using the divider.
- Measure the length of each marked portion.
- To get the distance between A and B just add the length of the entire portion together.
