What are tiered area diagrams

1.4.3. Features of location and area chart maps

Means of representation

Local signatures or diagrams are used as design elements for diagram maps (Hake et al. 2002, p. 467):

• Local signatures are divided into pictorial and geometric signatures. In their appearance, image signatures have a qualitative relationship to the value to be represented, geometric signatures are reduced to simple geometric shapes.
The size of the signature is relative to the value to be displayed. The transition between different values ​​can be made in stages, continuously or by means of value units.

• In the case of tiered displays, the size or shape of the signature changes by leaps and bounds. The prerequisite is the formation of value groups.

• The continuous display leads to a continuous change in the object size depending on the object quantity.

• When represented by value unit signatures, each signature represents a value unit. The quantitative information is formed as the sum of the individual value units.

• Diagrams are used if the object quantities are also broken down in terms of quality or time (for example the amount of precipitation per month). In principle, all diagrams that were presented in lecture 2 can be used. the choice of diagram depends, however, on the properties of the data set to be displayed (see lecture V2).
 left picture: pictorial signatures (student work IKA); right picture: geometric signatures (Institute for Cartography 2004)

 continuous representation (student work IKA)
 Value unit signatures (Schulze 1983)

Legend

In order to make the map understandable for the reader, a legend with a detailed explanation of the diagrams used is essential for diagram maps. The following is an example of a chart legend. You can explore them interactively.

interactive example of a legend (Y. Isakowsky, 2003)

Object reference

Statistical data in diagram maps can relate to specific locations or point locations such as cities or to entire areas. A distinction is therefore made between location diagrams and area diagrams. The cartographic options differ in some cases for the two map types. In the following two chapters, the location and area diagram maps are examined and explained individually.