A map is a representation of a part or whole of the earth's surface on a two-dimensional surface. Topographical maps, commonly known as topo sheets, are special maps prepared by the survey department that show a three-dimensional surface on a two-dimensional sheet of paper. In India they are prepared by the Survey of India (SOI). Reading them needs a clear understanding of conventional signs and symbols, colours and marginal information.
1. Map Reading and Topographical Maps
- A map is a good guide, but the user needs some skill to follow the direction and information given by it.
- Map reading denotes the formation of the visual picture of the ground depicted on a map. It requires a good deal of practice.
- The best way to become familiar with the topography of a region is to compare its topographic map with the actual area through a field visit called ground truthing.
- No one can collect direct information about the whole earth in a lifetime, but a student can get a large amount of information about the earth from topographic sheets.
- In India, topographic sheets for the whole country are prepared by the Survey of India (SOI).