Searching for Color Boundaries on Maps

Searching for critical information is a fundamental component for most map-reading processes. The mapmaker, therefore, must understand the underlying processes involved in human visual search and consider these processes when designing maps. Color is often used as a tool to clarify maps. To fully understand the use of color and visual search processes, mapmakers need to go beyond subjective techniques for applying color to maps. This entails a deeper understanding based on knowledge of the physical, physiological, and perceptual nature of color and human visual processes. The purpose of this study is to examine the interaction between color and the visual processes people use to search maps. An experiment was designed to determine the effectiveness of color using perceptually unique hues defined by Abramov and Gordon (1994). An analysis of variance on reaction times indicated that color strongly affected visual search, especially if the color was yellow. The Euclidean distance between target color had a significant effect on search time, although it appeared to be nonlinear. Whether the target boundary was based on luminance, hue, or both luminance and hue also had a significant effect on reaction times. In addition, geographers appear to have an advantage over nongeographers when searching for information on maps.