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scatter_matrix

Produces a scatter_matrix with optional trend fitting histograms, and Gaussian kernel density estimation.

The x-limits and y-limits are set to be 120% of the range of the data. The subplots are also configured to be square. The plot resolution increases with the number of variables plotted.

Example

The simplest example is to load the data into a DataFrame and tell scatter_matrix() what factors you would like in the matrix.

The defaults will give you factor labels down the diagonal and perform linear trend fitting for the subplots above the diagonal.

>>> df=DataFrame()
>>> df.read_tbl('data/iqbrainsize.txt', delimiter='\t')
>>> df.scatter_matrix(['CCSA','FIQ','TOTSA','TOTVOL'])

produces ‘scatter_matrix(CCSA_X_FIQ_X_TOTSA_X_TOTVOL).png’

scatter_matrix(CCSA_X_FIQ_X_TOTSA_X_TOTVOL).png

Example with diagonal=’hist’

Specifying diagonal=’hist’ produces 20 bin histograms along the diagonal. The y-axis labels do not relate to the frequency counts.

>>> df.scatter_matrix(['CCSA','FIQ','TOTSA','TOTVOL'],
                      diagonal='histogram')

produces ‘scatter_matrix(CCSA_X_FIQ_X_TOTSA_X_TOTVOL,diagonal=hist).png’

scatter_matrix(CCSA_X_FIQ_X_TOTSA_X_TOTVOL,diagonal=hist).png

Example with diagonal=’kde’ and alternate_labels=False

Specifying diagonal=’kde’ produces kernel density estimation plots along the diagonal. The y-axis labels do not relate to the density estimates.

Special care was taken to make sure the appropriate labels and ticks are plotted regardless of the number of variables or number of plots specified. With matrices with 5 or more variables become a bit hard to reconcile with the alternating ticks and labels. If you would like all the ticks on to the left and bottom and all the variable labels to the top and right specify just need to specify alternate_labels=False.

>>> df.scatter_matrix(['CCSA','HC','FIQ','TOTSA','TOTVOL'],
                      diagonal='histogram')

produces ‘scatter_matrix(CCSA_X_HC_X_FIQ_X_TOTSA_X_TOTVOL,diagonal=kde,alternate_labels=False).png’

scatter_matrix(CCSA_X_HC_X_FIQ_X_TOTSA_X_TOTVOL,diagonal=kde,alternate_labels=False).png
This software is funded in part by NIH Grant P20 RR016454.
© Copyright 2012, Roger Lew. Created using Sphinx 1.1.3.