Radar Series, used to create a Radar Chart (Spider Chart, Star Chart), is rendered to a circular graph and is used primarily as a multi-parameter data comparison tool.
Multi Measure Radar Chart
Multi measure radar chart is used to compare items by different, not related measures.
Radar Area Chart
Compared, areas covered by different data series form a general presentation of their relation, without losing the detailed information for every single parameter. Series that cover larger area are commonly considered to have a higher rating.