Practical GIS

Understanding map scales

When zooming around the map, we could notice the Scale changing in the status bar. GIS software (apart from web mapping solutions) usually use scales instead of zoom levels. The map scale is an important concept of cartography, and its use was inherited by GIS software. The scale shows the ratio (or representative fraction) between the map and the real world. It is a mapping between two physical units:

For example, a Scale of 1:250,000 means 1 centimeter on the map is 2500 meters (250,000 centimeters) in the real world. However, as the map scale is unitless, it also means 1 inch on the map is 250,000 inches in the ...