Question

What do the following numbers in grid square 1718 and 1818 mean?
(i) 280.

Answer 1

Hint: The numbers marked in the grid box 1718 and 1818 are used to find the slope of the land in the topographical map and depends on the contour interval, which is generally 20 metres.

Complete Answer: Since the number 280 is mentioned in red colour in between a running free line of red colour, it denotes the contour height. This is due to the fact that red coloured free line is used to depict the contour height and also the red text in between that line denotes the contour height.

Note: The other kinds of height that are present on the map are triangulated height and spot height which are important for survey purposes.