MAPS AND CHARTS 



73 



Type Forms 



The work on printed materials indicates 

 that when kinds of t3T)e differ in legibiUty, 

 the difference can usually be understood in 

 terms of such factors as size, boldness, inter- 

 nal and external spacing, and simplicity of 

 form. On pohtical maps especially, but to 

 some extent also on charts, some names have 

 to appear in small type. In view of the use 

 of faint night lighting to protect dark adap- 

 tation, it might be profitable to design a type 

 for maximum discrimination in terms of 

 visual receptor capacities. Mr. S. W. Boggs, 

 geographer of the State Department, who 

 has analyzed the problems of map typog- 

 raphy in detail, suggests that internal corners 

 of the letters be exaggerated in the originals, 

 as a protection against photographic and 

 visual fining in.^ 



Type forms are commonly used to dis- 

 tinguish different classes of geographic fea- 

 tures, both forms and sizes to distinguish 

 sizes of towns. A study of easily distinguish- 

 able forms within the limits of good legibiUty 

 would be worth while. 



The legibiUty work indicates that lower- 

 case words are more readable than capitals at 

 reading distance. The relative merits of the 

 two should be tested in the map situation. 



Symbols 



Maps and charts require a large number of 

 standardized symbols besides letters and 

 digits. Lists are readily available (36, 60). 

 Some are isolated characters, others apply 

 to areas and indicate physiographic features. 

 The tradition is to make a symbol suggestive 

 of the thing it represents, but many symbols 

 have necessarily become conventionaUzed, 

 and in some cases the differentiating details 

 are minor. The work on letters and digits 

 suggests that a search for areas of confusion 

 among other symbols should prove worth 

 while. 



In relatively new areas, such as in the air 

 and undersea, symbols have to be found to 



^ Personal communication 



represent new concepts. It would be de- 

 sirable under these circumstances to deter- 

 mine experimentally which of several pro- 

 posed symbols suggests, on first impact to 

 the largest number of people, the thing it is 

 supposed to represent. 



Color and Night Lighting 



Among the problems of map and chart 

 design for which the Uterature on printed 

 materials affords little help is that of color. 

 Certain conventions of color usage are sanc- 

 tioned by jidde acceptance: e.g., blue for 

 water, green for vegetation, and red or black 

 for cultural features. Other appUcations of 

 color, as for elevation tinting, are still to 

 some extent in the trial-and-error stage. 

 Experimental pre-tests with colored mate- 

 rials are necessarily expensive, but probably 

 less so than unsuccessful large-scale trials. 



Night lighting creates special problems: 

 first, that of getting enough light to make the 

 charts readable without ruining dark adap- 

 tation, and second, the distortion of color 

 values if the source differs in composition 

 from dayUght. The all-purpose maps on 

 fluorescent paper, tonal-keyed for red light, 

 are designed to solve the first of these prob- 

 lems. It has been reported that, at bright- 

 nesses which make the maps readable at lap 

 distance, dark adaptation is impaired 0.6 

 log unit by a greenish-yellow fluorescent 

 map surface and 0.3 log unit by a red 

 surface, and that night acuity is impaired 

 seriously by neither (1, 34). A current need 

 seems to be for a stable material fluorescing 

 red. (For data on several fluorescent mate- 

 rials, see Chapanis, 13.) 



Under red floodUghting, red symbols (e.g., 

 for buoys) are not visible. Magenta, which 

 shows dark under red light, has been substi- 

 tuted. Hue differences are, of course, lost, 

 and brightness relations are changed. A 

 thorough study of possible color arrange- 

 ments, in relation to the spectral properties 

 of the eye, available materials, and several 

 Ught sources, is in order. 



