Histograms

Data Histogram

This command is used to plot the data as histogram bars. Each data x value will be used as the center point of a histogram bar. The corresponding y value will be used as the height of the bar to draw.

The shape of the histogram is controlled by specifying the cell width of the histogram cell to shade each of the data points, offset (optional), and bar base (optional). The horizontal placement of each bar is adjusted using the optional offset (default 0), while the relative location of the base of the histogram bars are fixed to either of the window upper or lower limits, or zero; using the optional bar base value.

NOTE - the user must define the Data_Window, Data_Viewport, and Data_Projection commands to establish the proper coordinates for drawing the histogram. A non-zero offset may be used when drawing multiple bar per cell histograms. You must execute an Axis() command to provide the labelling for the histogram.

There are 3 or more parameters:

x axis cell width - the width to draw each histogram cell.

x axis cell offset - the optional offset to adjust the horizontal placement of each histogram cell (default 0).

bar base - the optional position of the base of each histogram

bar (default 0).

0 » base at the minimum y value as specified by the Data_Window() command.

1 » base at the maximum y value as specified by the Data_Window() command.

2 » base at the y value of zero.

xyz matrix - a matrix containing the x, y, and z data as 3 columns.

or

x, y, and z vectors- 3 vectors containing the data to be plotted.

Data_Histogram(x axis cell width,[x axis cell offset,[bar base]]);
Data_Histogram(x cell width,[x cell offset,[bar base]],matrix);
Data_Histogram(x axis cell width,[x axis cell offset,[bar base]],x vector, y vector, z vector);

/* Draw a 0.5 unit wide bar 0.5 units to the left of the x value */

See the example Histograms