Latitude and longitude: how to read coordinates

Read latitude first, then longitude

Every coordinate pair in this guide gives latitude first, then longitude. Latitude runs from 90° south to 90° north; longitude runs from 180° west to 180° east. The equator is latitude 0°, and the prime meridian is longitude 0°. You need both values to identify a position.

A worked example

Point A is at 20° N, 30° E. Find the 20° north line, then follow it to the 30° east line. Written as a signed latitude-first pair, that is (20, 30). Point B is south of the equator and west of the prime meridian, so its pair is (−20, −30). The minus signs indicate direction.

Latitude 0° is on the equator: neither north nor south. Longitudes 180° E and 180° W mark the same meridian. At either pole, all longitude lines meet, so changing longitude there does not identify a different point.

Try it

• 1. Which point is at 20° S, 30° W?
• 2. Write point D as a signed latitude-first pair.
• 3. What is point C’s latitude, and what line is it on?
• 4. Are (20, 30) and (30, 20) the same latitude-first position?
• 5. Is 95° N a valid latitude?

Check your answers

• 1. B.
• 2. (40, −60).
• 3. Latitude 0°; the equator.
• 4. No. Swapping the coordinates changes both the latitude and the longitude.
• 5. No. Latitude stops at 90° north and 90° south.

Why a degree is not a fixed distance east to west

Longitude lines meet at the poles, so a degree of longitude covers less ground as you move away from the equator. The evenly spaced practice grid helps you read coordinates. It does not mean every rectangle on Earth has the same width or area.

• Use a world map to recognize hemispheres
• Locate the oceans on a world view
• Review north, south, east and west