Using to specify the desired plots

The desired plots are specified by creating an object of class ClawPlotData that contains specifications of what figures should be created, and within each figure what sets of axes should be drawn, and within each axes what items should be plotted (lines, contour plots, etc.).

Plotting Data Objects

More details about each class of objects can be found on these pages:

For examples, see Plotting examples in 1d.


The approach outlined below may seem more complicated than necessary, and it would be if all you ever want to do is plot one set of data at each output time. However, when adaptive mesh refinement is used each frame of data may contain several grids and so creating the desired plot requires looping over all grids. This is done by the plotting utilities described in Plotting options in Python, but for this to work it is necessary to specify what plot(s) are desired.

Most example directories contain a file that contains a function setplot(plotdata). This function sets various attributes of plotdata in order to specify how plotting is to be done.

The object plotdata is of class ClawPlotData. The way to set up the plot structure is to follow this outline:

  • Specify some attributes of setplot that determine what sort of plots will be produced and where they will be stored, e.g.:

    plotdata.plotdir = '_plots'

    will cause hardcopy to go to subdirectory _plots of the current directory. (Attributes like plotdir that are only used for hardcopy are often set in the script rather than in setplot. See Specifying what and how to plot.)

    There are many other ClawPlotData attributes and methods.

  • Specify one or more Figures to be created for each frame, e.g.:

    plotfigure = plotdata.new_plotfigure(name='Solution', figno=1)

    plotfigure is now an object of class ClawPlotFigure and various attributes can be set, e.g.:

    plotfigure.kwargs = {'figsize':[8,12], 'facecolor':'#ff9999'}

    to specify any keyword arguments that should be used when creating this figure in matplotlib. The above would create a figure that is 8 inches by 12 inches with a pink background.

    For more options, see the matplotlib documentation for the figure command.

    There are many other plotfigure attributes and methods.

  • Specify one or more Axes to be created within each figure, e.g.:

    plotaxes = plotfigure.new_plotaxes()

    Note that new_plotaxes is a method of class ClawPlotFigure and creates a set of axes specific to the particular object plotfigure.

    plotaxes is now an object of class ClawPlotAxes and various attributes can be set, e.g.:

    plotfigure.ylimits = [-1, 1]

    There are many other ClawPlotAxes attributes and methods.

  • Specify one or more Items to be created within these axes, e.g.:

    plotitem = plotaxes.new_plotitem(plot_type='1d_plot')

    Note that new_plotitem is a method of class ClawPlotAxes and creates a plot object (e.g. line, contour plot, etc) specific to the particular object plotaxes.

    plotitem is now an object of class ClawPlotItem and various attributes can be set, e.g.:

    plotitem.plotstyle = '-'
    plotitem.color = 'r'

    for a solid line that is red.

    There are many other ClawPlotItem attributes and methods.

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