Taxonomy of Data Visualization Methods - Data Visualization: A Successful Design Process - page 121

Description : A radial chart displays data around a concentric, circular layout. The
example shown in the following image shows the status status across a number
of different categorical measures relating to gay rights for each state in the U.S.,
arranged to indicate approximate geographical relationships. A slight visual
shortcoming associated with a radial chart is the fractionally distorted prominence
of the segments on the outside rings which end up being larger (due to arc length)
than those on the inside. Often radial charts are used for showing data over time
but this only works when the sequence is continuous (such as a 24 hour clock).
Image from "Gay rights in the US, state by state" ( http://www.guardian.co.uk/
world/interactive/2012/may/08/gay-rights-united-states ),
created by Guardian in America Interactive
Glyph chart
Data variables : Multiple x categorical, multiple x quantitative.
Visual variables : Shape, size, position, color-hue.