DENSITY command

Syntax: | `DENSITY { x y } z`
Qualifiers: | `\GRADIENTS, \DITHERING, \DIFFUSION, \BOXES, \PARTIAL, \XPROFILE, \YPROFILE, \BORDER, \AXES, \RESET`
Defaults: | `\GRADIENTS, \-PARTIAL, \-XPROFILE, \-YPROFILE, \BORDER, \AXES, \RESET`

This command produces a density plot for either data contained in a matrix or a scattered set of points contained in three vectors.

Density plot types

There are four types of density plot available. The default, requiring no special qualifier, uses color gradients. Other types are chosen by using the appropriate qualifier.

density plot types | qualifier
color gradients | `\GRADIENTS` (default)
dithering with points (grey scales) | `\DITHERING`
diffusion with points (grey scales) | `\DIFFUSION`
scaled rectangles | `\BOXES`

Draw axes

By default, axes are drawn for the density plot. If the density plot is to be overlayed on an existing set of axes, use the `\-AXES` qualifier and no axes will be drawn. The axis scales will be left at their current values.

Draw rectangular boundary

The `\BORDER` qualifier is valid only if matrix data is entered. By default, the rectangular boundary of the matrix is outlined within the axes. If you do not want this boundary to be drawn, use the `\-BORDER` qualifier.

Zoom in

By default, the entire range of possible density levels will be used to determine the minimum and maximum density levels. If the `\PARTIAL` qualifier is used, the minimum and maximum density levels will be determined by the region contained within the axes. To zoom in on a particular region for more detail, pre-set the axis scales, using the `SCALES` command, before entering the `DENSITY` command.

Profiles

The qualifiers `\XPROFILE` and `\YPROFILE` are valid only if matrix data is entered.

If the `\XPROFILE` qualifier is used, the columns of the matrix are summed, the sums are normalized to be between `0` and `1`, and a histogram of the normalized sums is drawn horizontally across the top of the graph.

If the `\YPROFILE` qualifier is used, the rows of the matrix are summed, the sums are normalized to be between `0` and `1`, and a histogram of the normalized sums is drawn vertically along the right side of the graph.

When a profile is drawn, the axis borders must also be set to allow space for the profiles, that is, `XUPPERAXIS` is set to `65%` if a legend is present or `85%` if there is no legend, and `YUPPERAXIS` is set to `80%`.

By default, `XUPPERAXIS` and `YUPPERAXIS` are reset to their former values. If the `\-RESET` qualifier is used, the axis locations are not reset.

GRADIENTS
DITHERING
DIFFUSION
BOXES