Guides

Answers to common questions about maps and measuring, written by a GIS specialist.

• How to draw a radius on a map
  Draw a circle with an exact radius around any place on a map, in miles or kilometres, and share or export it. Step by step, with notes on accuracy.
• How accurate is measuring distance on a map?
  Why distances measured on a flat web map can be wrong by a factor of two, how big the error of the sphere formula is, and how to measure to the metre.
• How to find the elevation of a location
  Find the height above sea level of any point on a map, your current position or an address, and learn how accurate online elevation data really is.
• UTM vs latitude and longitude: what is the difference?
  How UTM coordinates in metres differ from latitude and longitude in degrees, how UTM zones work, when to use which, and how to convert between them.