Latitude and longitude: how to read a map coordinate

Two reference lines

The Equator is 0° latitude, while the poles are 90° north and south. Longitude is measured from the 0° Prime Meridian associated with Greenwich, reaching 180° east or west. NCERT explains these as angular measurements rather than ordinary distances in kilometres.

Latitude lines are parallels. Longitude lines, or meridians, meet at the poles. Their different geometry is a useful reason not to memorise a globe as if it were a rectangular sheet with evenly spaced distances everywhere.

An original worked example

Consider a fictional classroom coordinate: 20°N, 75°E. The first component places the point north of the Equator; the second places it east of the Prime Meridian. This example illustrates the notation and is not supplied as the exact location of a named town.

Changing the N to S moves the example into the southern hemisphere. Changing E to W changes its side of the Prime Meridian. The numbers alone are insufficient if the direction letters or sign convention are missing.

Mistakes to catch in revision

Do not confuse the direction in which a line runs with the direction its number measures. A parallel runs east–west around the globe, but its latitude tells you how far north or south it lies. A meridian runs north–south, but longitude measures east or west.

For practice, draw the Equator and Prime Meridian, mark a point in each of the four resulting broad regions, then label each point using N or S and E or W. Explain each label aloud. This exercise tests understanding of reference lines instead of only remembering the words. Always check the coordinate order used by a mapping service before entering values.

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