Map Work and Practical Geography
Map Work and Practical Geography tests whether you can read and construct maps: scale, direction, conventional signs, contours, topographical sheets and simple statistical diagrams. Calculations must show the method and carry units.
Scale
- Representative fraction (RF) is unit-free: 1:50,000 means 1 cm on the map equals 50,000 cm on the ground.
- Statement form: 1 cm = 0.5 km. Convert cm to km by dividing by 100,000.
- A graphical or linear scale survives enlargement and reduction of the map; an RF does not.
- Large scale (1:10,000) shows a small area in great detail; small scale (1:1,000,000) shows a large area in little detail.
Contours and direction
- The contour interval is constant; closely spaced contours mean a steep slope, widely spaced ones a gentle slope.
- A contour V pointing upstream marks a valley; closed rings with hachures mark a depression.
- Grid references are read easting first, then northing.
Worked example
Two villages are 6 cm apart on the map; the ground distance is 3 km. Convert: 3 km = 3 × 100,000 = 300,000 cm. RF = 6 : 300,000 = 1 : 50,000. Check: 1 cm = 50,000 cm = 0.5 km, so 6 cm = 3 km, consistent. Always state both the RF and the check line.
Traps
Dropping the two zeros in the km-to-cm step. Writing "1:50,000 km", which is meaningless because RF has no unit. Reading northing before easting. Measuring a curved road with a straight ruler instead of string or dividers. Assuming the contour interval equals the highest spot height.