Managing Multiple Plots

Managing Multiple Plots

When you want several plots sharing the same page, you have some design decisions to make:

is a simple tiled layout adequate?
do they share headings?
do they share a common key?

There are several examples to look at.

Sambars – four quite independent plots in a simple 2-by-2 grid
Intercepts – two quite different plots, independently positioned, but with a common key
Twopies – with a common heading, separate key
SmallMultiple – 12 miniatures, each showing a plane of some 3D data
Thumbnails – the examples used for the Rain Reference Card

Some things to note
If you want to box and title the entire set of charts as one (Twopies is a good example) you must do this first, and use chNul to make an empty plot that just flushes out the ‘boilerplate’.

chSet 'heading' 'Several Charts'
chSet 'style' 'boxed'
chNul

Now you can use chNew x1 y1 x2 y2 to define the plotting space for the first chart (note that points are used here, and that we are in an (x,y) system, not a (row,col) system ...

chNew 0 0,72×5 3  © Convert from inches!

By default, RainPro will wipe the space for you with a white rectangle. Because piecharts are round (!) this prevents you from spacing them as close as you would like (the second one takes a nasty notch out of the first), so:

chSet 'box' 'nowipe'

comes to the rescue here.

RainPro also assumes that all the charts are to share a common key, so that whenever it encounters chSet ‘key’ ‘One,Two’ it simply adds it to the stack of key information to be output at the end of the plotting process by chClose. If you want to key each chart separately – see Thumbnails – then you must flush out the keys at the end of each section with chWriteKey Ā.

Often, the common key needs to be positioned outside any of the individual charts. The best example of this is probably Intercepts, which draw two overlapped charts and a boxed key in the lower right corner. This is done by adding:

 chNew Ā   © default is entire plot region
 chWriteKey 80 20  © notional co-ordinates

at the end. This relies on the fact that RainPro establishes a default (x,y) co-ordinate system as (0,0)-(100,100) whenever you start a new chart. As soon as you plot something (the exception being a piechart) the co-ordinates become the axes of the graph you drew first within that plotting region. Keys are positioned (like notes) using this co-ordinate system.