Histogram Tool How to

4. In the Histogram Line Color dialog box, click MB1 in the color palette or enter a number in the Selected Color text field and press <Return> to choose the new color.

5. In the Histogram Attributes dialog box, click OK or Apply to apply the color change to the lines in the histogram.

Changing the Fill Color (Histogram Tool)

The procedure for changing the fill color for the histogram includes these steps:

1. (optional) Use the WzIPColorEdit VDA Tool to load a color table.

2. Select Attributes=>Histogram Attributes. This brings up the Histogram Attributes dialog box.

3. Click MB1 on the Fill Color button. This brings up the Histogram Fill Color dialog box.

4. In the Histogram Fill Color dialog box, click MB1 in the color palette or enter a number in the Selected Color text field and press <Return> to choose the new color.

5. Select the Fill Histogram selection box in the Histogram Attributes dialog box if it is not already selected).

6. In the Histogram Attributes dialog box, click OK or Apply. The histogram will fill with the color you defined.

note	To change the background color of a histogram or the color of the rectangle used to make data selections, choose Attributes=>View Attributes to bring up the View Attributes dialog box.

How Bin Size and Number of Bins are Calculated

The relationship between the number of bins in the histogram and the bin size is given by the following equation:

number_of_bins = ( [MAX(data) - MIN(data)] / bin_size )

When you select Bin Size as the bin method in the Histogram Attributes dialog box, PV-WAVE uses the value in the Bin Size text input field as the bin_size in the above equation to calculate the number_of_bins.

When # of Bins is selected as the bin preference in the Histogram Attributes dialog box, PV-WAVE uses the value in the # of Bins text input field as the number_of_bins to calculate the bin size:

bin_size = ( [MAX(data) - MIN(data)] / number_of_bins )

The default bin size is 1.

Changing the Bin Size

You can increase the width of the of bins (steps) in your histogram by raising the value for Bin Size. This results in fewer bins in the histogram. Lowering the value for Bin Size results in more, narrower bins.

The procedure for changing the size of the bins in the histogram plot includes these steps:

1. Select Attributes=>Histogram Attributes. This brings up the Histogram Attributes dialog box.

2. Click MB1 on the Bin Size radio button.

3. Type a value in the Bin Size text field to adjust the overall height of the histogram.

4. In the Histogram Attributes dialog box, click Apply or OK.

note	If the variable you are using is byte data, the Bin Size value must be larger than 1.

Changing the Number of Bins

You can increase or decrease the number of steps in your histogram by adjusting the number of bins for the plot. Lowering the value for # of Bins yields fewer, wider bins (steps). Raising the value for # of Bins increases the number of bins (steps), narrows the width of the bins, and shortens the height of the bins.

The procedure for changing the number of bins in the histogram plot includes these steps:

1. Select Attributes=>Histogram Attributes. This brings up the Histogram Attributes dialog box.

2. Click MB1 on the # of Bins radio button.

3. Type a value in the # of Bins text field to adjust the width and number of bins in the histogram.

4. In the Histogram Attributes dialog box, click Apply or OK.

Displaying a Variable in a Histogram Tool

Before you can display a variable in the Histogram Tool, the variable must already exist on the $MAIN$ level of PV-WAVE.

Use any of the following methods to display a variable in a Histogram Tool:

Open a Histogram Tool from the Navigator when one or more variables are on the variable selection list. The variable(s) on the variable selection list are automatically plotted when the Histogram Tool is opened (assuming the variable(s) are of an appropriate type and dimension). See Displaying a Variable in a VDA Tool Started from the Navigator for more information.

Import a variable. To do this, use the File=>Import Variable(s)

Export selected data from another VDA Tool using the File=>Export Selected Data function in the source VDA Tool.

Supply a variable name as a parameter to the Histogram Tool command. For example:

WAVE> WzIPHistogram, population_data

where population_data is a variable on the $MAIN$ level of PV-WAVE.

Button Bar Buttons

The Button Bar contains functions for editing graphical elements, selecting data and graphical elements, and adding graphical elements.

note	Position the pointer over a button to see its name printed just below the Button Bar. If a button is inactivated, no name will appear.

	Redraw—Redraws the current view and updates the view with any data changes.
	Cut—Cuts the selected graphical elements. A cut object can be pasted into the same graphics area or into the graphics area of another VDA Tool.
	Copy—Copies the selected graphical elements to a clipboard. A copied object can be pasted into the same graphics area or into the graphics area of another VDA Tool.
	Paste—Pastes the contents of the clipboard in the graphics area of a VDA Tool.
	Delete—Removes the selected graphical elements from the plot window and redraws the view. When a graphical element is deleted, it is not added to the clipboard. Therefore, you cannot paste or in any other way restore an item that has been deleted.
	Data Select—Lets you select a subset of the data that is plotted in the view window. Use the mouse to select a point or draw a rectangle around the data you want to select. Selected data can be exported to another VDA Tool with the File=>Export Selected Data command. Information about the selected data is printed in the Message Area.
	Irregular Data Select—Lets you draw an irregular boundary around a specific region of interest in your data. Press and drag the left mouse button to define the irregular region. The region closes when you release the mouse button. Selected data can be exported to another VDA Tool with the File=>Export Selected Data command.
	Object Selection—Lets you select graphical elements in the plot using the mouse. Graphics elements include text, lines, rectangles, legends, and axes. Selected graphics elements can be cut, copied, pasted, deleted, or grouped.
	Create Text Object—Add words and phrases to accentuate important trends and differentiate features of the view. Use MB1 to pick a starting point for the text, then enter the text. Press <Return> when you are finished entering text.
	Create Line Object—Add a line to the display area to emphasize a particular value or to visually connect text to some feature of interest elsewhere in the view. Press and drag MB1 to define the line. Press and drag <Control>-MB1 to constrain the line to be horizontal or vertical.
	Create Box Object—Add a box to the display area to enclose a region of special interest. Press and drag MB1 to define the corners of the rectangle. Press and drag <Control>-MB1 to create a square.
	Create Ellipse Object—Add an ellipse to the display area to enclose a region of special interest. Press and drag MB1 to define the bounding box of the ellipse. Press and drag <Control>-MB1 to create a circle.