Symbolisation and Visual Variables Questions and Answers

Answer: C

Correct answer: the order in which elements draw the eye

The visual hierarchy is what the reader notices first, second and third, and it is built with contrast, weight, value and saturation rather than with position. A well-designed thematic map puts the theme at the top of that order and the base map below it; when the hierarchy is flat, the reader has no way of knowing what the map is about.

Answer: D

Correct answer: uses a small number of fixed symbol sizes

A graduated symbol map classifies the data first and assigns one symbol size per class, so the reader matches sizes against a legend of discrete steps. A proportional symbol map scales every symbol continuously by its own value. The graduated form is easier to read and to compile; the proportional form preserves the detail that classification throws away.

Answer: A

Both are true and the reason explains how: with no grouping step, no differences are flattened. The trade is that the reader can no longer match a tone to a stated range, so precision in the data is bought with imprecision in the reading.

Answer: B

Each class is 50 wide, so the third runs from 100 to 150 and contains 137. Dividing the value by the class width and rounding upward gives the class number directly, which is quicker than reading the boundaries off the legend one at a time.

Answer: C

Bertin treated the two dimensions of the plane as variables in their own right, and indeed as the most powerful ones available. What distinguishes the other six is that they are varied at a position that the data have already fixed.