Scale
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A ratio scale indicates the relationship between a distance on a map and the actual distance on the ground. It is commonly written as 1:X, where 1 cm on the map represents X cm in real life. To convert from a ratio scale to meters, the last two zeros are dropped; to convert to a ratio scale from meters, two zeros are added. Larger ratio scales like 1:100,000 show less detail over a larger area compared to smaller ratio scales like 1:20,000 that show more detail over a smaller area. The scale allows distances and areas on the map to be calculated.
Scale
- 1. Scale: A ratio scale tells us what 1cm represents in centimetres eg 1:100,000 means 1cm represents 100,000 centimetres. When converting from ratio scale to metres you take off the last 2 zeros eg 1: 100,000 becomes 1000 metres. And vice versa when converting from metres to ratio add 2 zeros eg 500 metres becomes 1:50,000 Fill in the blanks below Ratio scales Sentence scale ___ kilometres 1: 200,000 1 centimetre represents 2000m km 1: 100,000 1 _______________________ 1 km 1: 75,000 1 _______________________ 0.75 km 1: 50,000 1 centimetre represents 500m ______ 1: 25,000 _________________________ 0.25 km 1: 10,000 _________________________ ______ 1: 5000 _________________________ 0.05 km 1: 1000 _________________________ ______ Maps drawn on progressively smaller scales increase the area of the earth that can be shown, but reduce the amount of detail that can be included. Maps drawn on progressively larger scales decrease the area that can be shown but enable more detail to be shown. This means, for example, that a map drawn to a scale of 1:20,000 covers a smaller area of the earth’s surface but shows much more detail than a map drawn to a scale of 1:100,000. Because the scale of a map shows the relationship between distances on the map and distances on the ground it can be used to calculate distances and areas.