Identification of Cartographic Symbols from TV Displays

Abstract

An experiment was conducted to investigate the resolution capability of TV displays in distinguishing details from line-maps and picto-maps, and to establish the relative merits of color and black-and-white TV display systems. The experimental variables included two display types, three map types, four symbol types, and three image-resolution levels. The results showed that a color display offered some advantage over a black-and-white display of equivalent effective resolution. However, a black-and-white system could provide the same performance at the expense of a slightly higher effective resolution. At an image-resolution level of nine TV-lines/mm, alphanumeric symbols were identified almost 100% correctly for all map types and display types. Area and line symbols achieved their maximum level of performance at five and seven TV-lines/mm, respectively. United States Geological Survey (USGS) 1:24,000 maps were significantly better than TOPOCOM line-maps and picto-maps.