GIS Files 1: Getting to grips with GIS

1.5: The significance of scale (1)

Scale basics

When looking at a paper map, probably the most important thing to bear in mind is the map scale. This is the relationship between the dimensions on the paper to the real distance on the ground.

If a building is 13 m long in the real world and a map depicts this length as 13 mm, the scale is 1:1000. Multiplying the distance on the map by the scale factor gives you the real world dimension.

In the world of GIS and computerised mapping things are more complicated. A description of scale can lose its meaning – the scale of the image on screen can depend on the monitor size. The image above may appear 13 mm long on some screens but not others.

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