Why is this relevant? How is it used?
Contour lines are lines drawn on a special kind of map called a topographic map. The contour lines are special, because they indicate a height – and every point along a given line must be at the same height. When looking at the range of lines, and their shapes, on a topographic map, we can tell whether the terrain is flat, highly, steep cliffs, or gradual slopes – just by looking at the contour lines.
Discussion
Contour lines.
Common errors
Common errors with contour lines are:
- not remembering that the height difference between contour lines, called the contour interval, is always the same on a map
- at the top of a hill, where there is a contour line around a point which is lower than the top of the hill, remembering that the top of the hill cannot be higher than the contour line plus the contour interval (otherwise there would be another contour line on the map)
How is this tested or examined?
Contour lines are typically examined by showing a topographic map and asking questions including:
- for a named point on the map, what is the height? If the point is on a contour line, it is easy. If it is not on a contour line, students must approximate between the nearby contour lines.
- what is the contour interval for the map (calculated by calculating the difference between adjacent contour lines)
Alternatively, multiple choice or short answer questions can ask for definitions of a contour line, or contour interval, or ask students to draw a topographic map with two hills and to label the contours to demonstrate understanding.
Further resources
Reading a map: great BBC resource
mygeoskills 