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V shaped contour line definition12/11/2023 The National Mapping Council of Australia Standards of Map Accuracy (2nd edition, 1975) stated in general terms that, 90% of tested contours and elevations interpolated from contours will be accurate to within one half a contour interval of their true height. Not more than 10% of well-defined features are in error by more than 5600 metres.Not more than 10% of well-defined features are in error by more than 2800 metresĪt 1:10 000 000 scale, the summation of errors from all sources results in map detail with a standard deviation of 3400 metres for well-defined features.Not more than 10% of well-defined features are in error by more than 1400 metresĪt 1:5 000 000 scale, the summation of errors from all sources results in map detail with a standard deviation of 1700 metres for well-defined features. General Reference maps will have no statement of map accuracy on the map layout however they must comply with the following statements of planimetric accuracy:Īt 1:2 500 000 scale, the summation of errors from all sources results in map detail with a standard deviation of 850 metres for well-defined features. Not more than 10% of well-defined features are in error by more than 140 metres. Not more than 10% of well-defined features are in error by more than 56 metresĪt 1:250 000 scale, the summation of errors from all sources results in map detail with a standard deviation of 85 metres for well-defined features. NTMS maps will comply with the following statements of planimetric accuracy:Īt 1:100 000 scale, the summation of errors from all sources results in map detail with a standard deviation of 34 metres for well-defined features.Īn alternative and equal way of expressing this error is: Geoscience Australia restricts its statements of Topographic Map Accuracy to well defined points. While Geoscience Australia's positional accuracy measurements for topographic data are given to encompass a feature's entire spatial representation. Geoscience Australia has carried out both error analysis and field tests to verify the positional accuracy of features on the existing mapping. Most commonly the well-defined points used in tests are at feature intersections. The term 'well-defined points' is used to define those locations which can be accurately identified on the map. The measure of accuracy given for topographic maps is the standard deviation. The use of a 'cartographic representation' of a feature maintained in its 'true position'. This error is applicable when the process of generalisation is independent from the source data capture/maintenance process.
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