4. On a sheet of graph paper, draw a base line the same length as the section you have just drawn (X-axis). Transfer all the markings and heights from your paper onto the base line.
5. Choose a vertical scale: In Fig. 22 the scale used is 2 cm = 100 m. 6. Draw a vertical line (Y-axis) at the left-hand edge of the base line and mark the vertical scale along this line. (2 cm = 100 m)
7. Using the heights marked on the base line, mark with a point each height using the vertical scale.
8. Join all the points. 9. Write the vertical scale you have selected (e.g. 2 cm = 100 m) and the horizontal scale (taken from the OS map) which is usually 1:50,000.
Fig. 22 Drawn cross section of Fig. 21
300 Vertical scale: 2 cm = 100 m 200 100
Walking route
N67 R480 Track
AB Distance
Remember: Always have a pencil, eraser, ruler and graph paper to do your sketches. A final sketch should always be the same shape as the original but not the same size. The sketch will always be smaller than the original. A sketch should never be traced.
10. Sketch maps How to draw a sketch map to half scale.
1. Count the number of grid squares across the top of the map and divide by two. This is the length in centimetres of the top and bottom of your frame.
2. Count the number of grid squares up the side of the map and divide by two. This is the length in centimetres of the left and right sides of your frame.
3. Using graph paper and a ruler, draw the frame of your sketch in the same shape as the OS map.
4. Using a light pencil, divide the map and sketch into three evenly-spaced rows and three evenly-spaced columns. Use these rows and columns to draw the items in the correct position and proportion.
5. Put a title and sub-zone letter on your sketch. 6. Mark the coastline and major lakes if shown. 7. Mark and label only what you have been asked to draw in the question.