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ch.Multiple – small multiples

Multiple plots are a very effective way of viewing high-dimensional data on a flat sheet of paper. Effectively this function automates the process of setting up a trellis and looping around it cell by cell.

ch.Multiple data


ch.Set('type' 'boxplot')
ch.Multiple yield by farm year

The chart type must be one of the standard RainPro charting functions, such as ‘Scatter’ or ‘Bar’ or ‘Frequency’. The call to ch.Multiple simply sets up a trellis with one cell for every unique value in the ‘by’ variable (the category variable) and loops around these values, plotting one chart in each cell. For every plot type except Frequency, it will autorange the data at the start, to ensure that all the plots are ranged the same. For Frequency plots you should set the Y-range and class-interval explicitly before you run the multiple, if you want all your miniatures to be ranged consistently.

ch.Set ('type' 'freq')('yr' 0 30)('xr' 10 70)('Classint' 10)   
ch.Multiple yield by year                            
View ch.Close

You can set the trellis-style to ‘snaking’ to have the plots work down the columns rather than across, and you can also set ‘paged’ which simply puts each plot on a separate page.

See also ...
Trellis – trellis of small charts
TrellisStyle – trellis style
TypeOfChart – chart type

Continue to: ch.Nul – flush output with no chart
© Copyright Causeway Graphical Systems Ltd 2003