Displays a correspondence analysis previously computed from a tm corpus.
This dialog allows plotting and showing most contributive terms and documents from a
previously computed correspondence analysis (see corpusCaDlg).
It allows plotting any dimensions of the CA together, showing either documents, terms,
or variables set on the corpus using the Text mining->Manage corpus->Set corpus variables menu.
Compared with most correpondence analyses, CAs of a corpus tend to have many points to show Thus, the dialog provides two sliders (“Number of items to plot”) allowing to show only a subset of terms, documents, the most contributive to the chosen dimension. These items are the most useful to interpret the axes.
The text window shows the active items most contributive to the chosen axis, together with their position, their contribution to the inertia of the axis (“Contribution”), and the contribution of the axis to their inertia (“Quality of Representation”). (For supplementary variables or documents, depending on the parameters chosen for the CA, absolute contributions are not reported as they do not exist by definition.) The part of total inertia represented by each axis is shown first, but the rest of the window only deals with the selected axis (horizontal or vertical).
The 'Draw point symbols for' checkboxes allow representing documents, terms and variables masses (corresponding
to the size of the symbols) and relative contributions (corresponding to the color intensities). See
the contrib argument to plotCorpusCa for details.