What is the characteristic of a symbol drawn proportional in size to represent the variable?

The characteristic of a symbol drawn proportional in size to represent a variable is known as a proportional symbol. This technique involves varying the size of a symbol (such as a circle) based on the magnitude of the value it represents. For instance, if the goal is to show population data, a larger circle would indicate a higher population in a particular area compared to a smaller circle, which would represent a lower population. This method effectively communicates differences in data values visually, allowing for quick interpretation of the variable being analyzed.

In contrast, isarithmic symbols represent continuous data across a surface using lines, showing gradients rather than absolute values. Choropleth symbols are used to categorize or shade areas based on class intervals of a variable, rather than varying symbol size based on the exact value. Contour symbols, on the other hand, are used to represent elevation or other quantitative data across a geographic area through lines connecting points of equal value. Each of these alternatives serves distinct purposes and employs different visual strategies to communicate information, highlighting why proportional symbols stand out for representing magnitude.