Principal Components Analysis PCA
This window shows plots of the sample
display options are selected from the panel below the graph.
The label radio box is used to select labelling for the samples. Select
display on the plot the names of the samples. Select
to show the
sequential number of each sample in the working data set. Select
remove labels from the plot.
The plot radio box allows sample scores, the eigenvectors (one for each species
or row in the working data ) or both to be plotted. If both are selected then the
biplot uses different axes to plot the scores and eigenvectors. The axes for the
scores are displayed at the bottom and on the left. Note that the eigenvectors are
labelled using column numbers used in the eigenvectors table. The display
cannot show labels and arrowheads so the eigenvectors are represented as lines
rather than vectors.
The axes displayed in the plot are selected using the Plot component (x) and Plot
component (y) drop down boxes. The default is axis 1 and axis 2, which will
display the relative positions of the samples with respect to the two largest
This shows both the vectors for the variables (species) and the positions of the
samples within the first two axes of the ordination space.
The diagram was created using the demo dataset powerstation_fish.csv.
#perimeterIn two dimensional plotting it is possible to display the perimeter of
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