A Psychophysical Study of Cartographic Symbols

Abstract : In two experiments the subjective volume of certain cartographic symbols was studied by the method of magnitude estimation. The stimulus material consisted of several sets of cubcl. illus. table, 12 refs. (Technical (Scientific) note no. 6) (Contract AF 61(052)300) (AFOSR-1247)Unclassified report DESCRIPTORS: *Visual perception, Perception, Measurement, Map reading. Open-ended Terms: Psychophysics. In two experiments the subjective volume of certain cartographic symbols was studied by the method of magnitude estimation. The stimulus material consisted of several sets of cubes and spheres, drawn with perspective and shadow. The total range of stimulus volume was 1:3,500. Psychophysical power functions yielded a good fit to all experimental data. The exponents varied from 0.56 to 0.82, most of them being close to the average value, 0.69. The results substantiate the tentative conclusion from a previous study, according to which volume estimates in the case of small projected solids essentially reflect perception of area, and this conclusion is further confirmed by a third experiment designed to throw additional light on this particular question. (Author)