Point symbols are the most commonly used proportional symbols in thematic mapping. Traditionally two types of symbols have been in use in this category -proportional squares and circles. These studies have reported malfunctioning of these symbol forms in terms of the errors reflected in response outputs of the magnitudes both in absolute and relative modes when these are read from the symbols placed in map environments. This malfunctioning of the symbol among other factors was ascribed to the type and design of symbol form and the legend provided on these maps. This paper examines the deficiencies in symbol form design of proportional circles and squares together with the existing design practices of legend design. An effort will also be made to improve symbol form by (1) adding (a) uniform gray area fills (b) graded gray area fills in the open circle and square form together with (2) an improvement in legend deign and its organisation. These design improvements will be tested experimentally by measuring the resulting improvements in terms of both efficiency and effectiveness of visual information processing. The experimental results have shown enhancements in both efficiency and effectiveness in information processing from maps due to proposed design improvement.

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The growing use of colour in thematic map design and production, particularly in GIS based mapping environments, brings to notice a state of affairs where at least certain basic rules are required to be made to help in better, effective and efficient use of colour. One approach towards this end appears in efforts towards making the map image and input from it more compatible with the human visual processing system. This entails selection and structuring of the visual variables and the ensuing sign system of map graphics into a map image in a way in which such structuring results in an increase in the efficiency of information processing system. Many aspects of use of these visual variables from the commonly used term colour i.e. hue, value and chroma in symbolisation of thematic maps have not been investigated individually in the areas as segregation of map image's focal realm form its peripheral realm or in other words the figure from its ground, organising perceptual groups, creating visual hierarchies by depth cues. The present paper attempts to fill certain gaps in studies related to the effects of the use of visual variables hue, value and chroma individually or in combination in map symbolisation on the preattentive stage of visual processing of information. These effects will be studied in case of area symbolised and line symbolised maps including those graduated point symbolised maps where colour dimensions are used as area fills in the blank outline symbol forms. Evidence in support of these effects will be sought from the experimental studies in design research in thematic cartography and psychology.

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