An Application of Subjective Scaling Techniques to Map Evaluation

Abstract

Subjective scaling techniques were used to obtain quantitative data from twenty-six pilots and ten navigators in order to determine the perceived dimensions of eighteen 1:250 000 scale maps and to assess the suitability of the maps for en route navigation of low altitude high speed aircraft. Comparisons were made between perceived dimensions and assessments of map efficacy and between pilots' and navigators' assessments.The perceived dimensions correspond to major known differences in cartographic content and coding and were associated with the assessments of map efficacy. None of the maps tested was ideal; and pilots tended to be more critical of the maps than navigators, perhaps because they have less time for map reading in flight. Pilots preferred maps with bold, distinctive layer tint colours for representing relief, and both groups preferred maps with reduced information content and less visual clutter. 1:250 000 scale maps for en route low altitude high speed flight should use smaller selection rates for features than on conventional 1:250 000 scale maps and should be designed to give a clear and unambiguous impression of features that are distinctive from the air.