The author describes the properties and mechanisms of visual perception in the context of their significance to the principles of symbol design as used in cartography. Map perception relies on the process of visual perception. Therefore, the knowledge of its inner workings in the map environment allows cartographers to construct cartographic symbols in agreement with the properties of the visual system.
Visual perception involves neurosensory processes taking place between the eye and the short-term memory. As such, they operate independently of the beholder’s consciousness and significantly influence the information received by the map user. The author discusses the mechanisms of human vision and the nature of the process of visual perception. It also shows the relationships between the image characteristic and the visual system’s properties such as the optical resolution, visual adaptation, reactions of inhibition and reinforcement, reactions to the image characteristics – as well as the phenomena of contrast, grouping and spatial arrangement.
The principles of constructing map symbols that have been developed in the long course of cartography, and based mostly on the map makers’ intuition, find validation in the light of properties and mechanisms of visual perception. As discussed in the paper, the fundamental properties and basic mechanisms of human vision support the view that knowledge of how the visual system works provides foundation for articulating new mapping guidelines and cartographers’ calls for stricter observance of cartographic principles are fully justified.
Map perception consists of numerous processes of information processing, taking place almost simultaneously at different levels and stages which makes it conditioned by many factors. In the article, a review of processes related to the perception of a map as well as levels and properties of perception which impact its course and the nature of information obtained from a map is presented. The most important process constituting the basis of a map perception is a visual search (eye movement). However, as stated based on the studies, the process is individual depending on the purpose of map perception and it may be guided by its image (visual search guidance) or by the knowledge of users (cognitive search guidance). Perception can take place according to various schemes – “local-to-global” or “global-to-local”, or in accordance with the guided search theory. Perception is divided into three processes: perceiving, distinguishing and identifying, which constitute the basis to interpret and understand a map. They are related to various degrees of intellectual involvement of the user and to various levels of questions concerning the relations between signs and their content. Identification involves referring a sign to its explanation in the legend. Interpretation means transformation of the initial information collected from the map into derivative information in which two basic types of understanding take place: deductive and inductive. Identification of geographical space objects on the map and the interpretation of its content constitute the basis to introduce information into memory structures. In the brain a resource of information is generated called geographic knowledge or spatial representation (mental map) which may have a double nature – verbal or pictorial. An important feature of mental maps is organization of spatial information into hierarchical structures, e.g. grouping towns into regions as well as deformation of spatial relations between individual elements and their groups independent of consciousness.
The process of map perception depends on various factors, including the nature, scale and map content, the degree of its complexity and compliance of the map language with cartographic principles. Important factors also include cartographic competencies of the recipient of a map conditioned by age, education and the task type. It is related to types of information about geographical space: semantic – concerning spatial references of particular objects and structural – connected to relations between elements of a map. Such relations may be determined at the regional or global level, they may concern qualitative or quantitative features as well as changes in time.
Nowadays, an important factor impacting the nature and consequences of map perception is the situation in which the process occurs. Traditionally, static and unchanging maps are used under other conditions than computer maps and navigation systems, making it possible to freely zoom in and zoom out the image and its spatial scope as well as to quickly go from one image to another.
Today, when the predominant way of map use is their perception on the screens of navigation systems, processes of map perception and factors conditioning it are also significant to understand the process. In the analysis of map perception, also tasks which are implemented using the map and the nature of information obtained by the map user must be taken into account.
Until the 1990s map perception research was one of the main parts of cartography as a scientific discipline. In the last years of the century map perception research fell out of favor as cartographers turned their attention to the new computer technology. In the first decade of the 21th century the problems of map perception became more frequent in cartographic journals.
The article recaps the main problems, theories and research conducted in the twentieth century. The main concepts connected with map perception are discussed: use, utilization, reception and interpretation. These terms are used differently in different research orientations. The author assumes that the terms: reception, reading and perception are unambiguous and perception should be treated as a complex of active and highly interactive processes, leading to identification and understanding of the visible image. The relation of perception research with theory of cartography are presented in three stages of development of the research. In the first, intuitive stage, very important role played eminent cartographers Max Eckert and Karl Peucker, who appreciated the role of human perception in cartography. The second stage began with the research initiated by A.H. Robinson in the 1950s. In the stage perceptual research contributed to the physical aspects of cartographic signs and the psychophysical orientation emerged. Perception has been accepted as an element of cartographic communication theory, modeling theory and cartographic semiotics. The third stage of perceptual research emerged as a result of criticism of empirical research effects. Cartographers turned to methods and theories of cognitive psychology and cognitive orientation was a main paradigm of the research. Perception is perceived as one of the elements of the human cognitive system and considered in the context of higher lever cognitive processes, participating in cartographic information processing. Two methodological approaches can be set apart: theoretical and experimental. In the theoretical approach the processing succession is considered and some models of cartographic processing models were presented. The first decade of the 21st century opens a new stage of perceptual research. It can be named cognitive-digital as the research is based on computer software and is concentrated on cognitive aspects of map perception.