Correlation Circle Plot
A correlation circle plot (or correlation circle) is a visualization used in Principal Component Analysis (PCA) to show how the original variables of a dataset relate to the principal components — and to each other.
Correlation Circle
A Correlation Circle chart is a circle of radius 1 where:
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Each original variable (feature) is drawn as a vector (arrow) from the origin.
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The X-coordinate value is the correlation of that series' feature column with the first dimension column.
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The Y-coordinate value is the correlation of that series' feature column with the second dimension column.
Correlation Circle Data Range
Data for the correlation circle plot must be arranged so that the last two columns are the PCA dimensions and every preceding column is a feature.
The PCA data depends on the feature values. However, you must provide the PCA data yourself, as LibreOfficeDev has no built-in function to compute it.
Example
Error bars, trend lines and area properties are turned off for this chart type, since a point stands for a worked out pair rather than for a value in a cell, and symbols are turned on because the tip of each arrow carries one.
The arrows take the line colour and width of their series, and line thickness is disregarded, which is what keeps a crowd of them apart.
The legend hands out the same symbol as the arrow tip, so a key can be matched to an arrow.
Grids are turned off by default for this chart as the matter is in the direction, angles and magnitude of the rays from the origin.