[Ref FAA-H-8083-18 Flight Navigator Handbook]

The ratio between any given unit of length on a chart and the true distance it represents on the earth is the scale of the chart.

Charts are made to various scales for different purposes. If a chart is to show the whole world and yet not be too large, it must be drawn to small scale. If a chart is to show much detail, it must be drawn to a large scale

Remember :

large area, small scale; small area, large scale


the smaller the denominator of the representative fraction, the larger the scale – examples: WAC 1:1,000,000 ; VTC 1:500,000

On aeronautical charts, the scale is indicated in one of two ways:

  1. representative fraction
    • This means one of any unit on the chart represents 500,000 of the same unit on the earth.
  2. graphic scale
    • could shown by a “graduated line” – usually is found printed along the border of a chart




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