#Uk air navigation charts series

For a navigator, the most desirable characteristic is to conserve accuracy of direction with respect to meridians of longitude and parallels of latitude because, if their coordinates are accurate, it is relatively easy for the navigator to determine where he is on the Earth’s surface and to plot bearings and tracks to get from one place to another. However, over the area represented by each 1:500 000 sheet, there is no discernable difference between a great circle and a rhumb line.ĭistances are accurate over both charts, and, in practical terms, shape and scale are conserved.Īll navigation charts, then, are projections which, though the task is not perfectly achievable, attempt to conserve on a flat surface as many of the characteristics of the true surface of the Earth as possible, to a greater or lesser degree of accuracy. On the ICAO 1:500 000 chart, a straight line represents a great circle on the Earth.

A straight line on a UK CAA 1:250 000 series chart is a rhumb line. On both charts, a straight line drawn to represent the desired track between two locations, represents a straight line on the Earth’s surface for the area covered by the chart. The two most widely used charts used in visual air navigation, in the United Kingdom, are the ICAO 1:500 000 series of charts and the UK CAA 1:250 000 series.Īs we have seen, both types of chart, which, if we take individual sheets from the series, cover only relatively small areas of the Earth’s surface, achieve quite a high level of success in reproducing many of the ideal properties of an aeronautical chart.

Latitudes and Longitudes should be easy to plot.

Great Circles should be straight lines.

Angles on the Earth’s surface should be represented by the same angles on the chart.

If the shape and area of features on a chart are not accurate, scaled-down versions of the same areas on the Earth’s surface, then the chart may confuse the navigator. Areas on the Earth’s surface should be shown as proportionally equal areas on the chart.Land masses should be represented with their true shape on the chart.If the ideal chart could ever be produced, its properties might be summed up as follows. PROPERTIES OF AN IDEAL AERONAUTICAL CHART.Īlthough, as you have seen, the spherical surface of the Earth can never be represented on a two-dimensional chart without the Earth’s surface undergoing some deformation, a high degree of accuracy can be achieved amidst the inevitable distortions.

Customer: Oleg Ostapenko E-mail: Oleg Ostapenko E-mail: 5: AERONAUTICAL CHARTS AND CHART-MAKING

#Uk air navigation charts series