ch.Trace – trace charts

chTrace – trace charts

This is a special chart type which plots a matrix of data on a set of equally-spaced parallel lines, like a seismograph or ECG trace.

chTrace mat

grapl.Trace tracedata

Examples

chSet('style' 'boxed,nolines,nomarkers,xyplot')
chSet'key' 'Temperature in °C'
chSet'grid' 'solid,NE'
chSet('hmar' 54 36)('ylab' 1 2 3 4)
chSet('head' 'Temperature Data from Iceland Field-study')('ycap' 'Probe')('xcap' 'time')('xtic' 1 1)('xs' 'date,grid')
chSet'nomarkers,lines'
chSet('is' 'xtic')('if' 'he,4,green')
chTrace(‘dt+‘hm),‘log[;1 2 3 4]
PG„chClose

This allows for surface-fill (ideal format for plotting resource-utilisation) and ‘kite’ styles (used for pollen diagrams, see Kite for an example).

 mm„6 12½0
 mm[1;]„12†0 0 1 2 2 3 3 3 2 1 1  © Oak
 mm[2;]„12†0 0 0 0 1 1 1          © Ash
 mm[3;]„12†0 1 1 1 2 2 2 2 2 2 1 1 1 © Birch
 mm[4;]„12†0 1 1 2 2 2 1 0        © Hazel
 mm[5;]„12†0 0 0 0 0 0 0 1 2 2 2 2  © Lime
 mm[6;]„12†0 1 1 1 2 3 3 3 3 2 1  © Elm
 chSet('head' 'Sample Kite Chart')
 chSet('yc' 'Species')('ys' 'atend,grid')('yl' 'Oak,Ash,Birch,Hazel,Lime,Elm')
 chSet'Xcap' 'Metres from Shoreline'
 chSet('style' 'rows,kite')('pattern' 4)
 chSet'is' 'xtick'
 chTrace mm
 PG„chClose

Currently this supports horizontal charts only – a vertical style will also be supported in the future. Note the addition of a logical ‘Inner’ axis so you can set ‘inner style/range/intercept’ and so on for the repeated small numbers which go with each line. The properties you may change are:

IS – inner style sets the tickmark type as for normal axes
IL – inner labels can be used to label each inner major tickmark
IF – sets the font for the inner-axis labels
IR – ranges the inner axis (all copies will be ranged the same)
IT – sets the tick intervals (major ticks only here)
II – sets the intercept value where the inner axis is drawn
IA – sets the ‘allowance’ (default 0.8) as a fraction of the space between adjacent trace lines (determined by the major Y-ticks). This may be set to a value >1 if you have a set of lines which move along very nearly parallel to one another. However this only works well with a plain inner axis as otherwise the ticks and labels collide.

See plots Iceland and Iceland2 in the linechart examples to compare a conventional series with the trace.