Map design and layout

 
Diffusion Phase
During this phase, the map reader sees only the visual outline of the map. Whether it 
is a reference map or a thematic map, the visual outline gives to the reader an idea of what the 
map is trying to lay emphasis on. According to Robinson the fundamental elements of the 
visual outline are:
1. The place,
2. The phenomena portrayed,
3. The position of the phenomena in the area, and 
4, The relative position of the symbols.
If the objective of the map is to lay emphasis on places, they should stand out 
distinctly in the map. This is done when we prepare a map showing location of cities. If the 
distribution of certain phenomenon are to be emphasized, the specific region where they are 
distributed should be made distinct and if certain things are to be emphasized within that area, 
first the area should be made distinct from its Surroundings and then the region where the 
phenomenon is distributed should be made distinct from the rest of the area. Finally, if the 
distribution of two different phenomena is to be given prominence, they should be made quite 
distinct by using contrasting colours or shades.
An arrangement of the type suggested above will make the prominent aspects of the 
map stand out from the rest of the aspects. Such an arrangement enables the map teader to 
instantly know the main thrust of the map as soon as he looks at it. The visual outline serves 
the same purpose as the chapter headings in a book. By making the outline prominent, the 
map maker is able to transform his products into effective instruments of visual 
communication.

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Differentiation Phase
In this phase of visual communication, the eyes of the map reader look for further 
details of the phenomenon portrayed in the map. A good map is marked with two 
characteristics of the data represented on it:
1. They are authentic, and
2. They are represented clearly, legibly and effectively.
Both the qualities must be present simultaneously. A clear, legible and effective 
representation is no substitute to correct representation, and vice versa is also true. A good 
balance has to be struck between accuracy and effective, clear and legible representation.
Presentation of symbols: To make a map clear and legible, symbols used must be 
adequately differentiated from each other. For example, all lines must be clear, sharp and 
uniform. To differentiate one line symbol from the other, we can either use varying thickness 
or varying designs of lines.