You can add two types of graphs to the Analysis Area:
• Histogram—Graphs a single feature.
• Scatter Plot—Graphs two features.
To create a graph
1 Click the New Histogram or New Scatter Plot toolbar button.
The New Histogram or New Scatterplot window appears, respectively.
Graph Bkgd Tool
Changes the background of the graphs to black or white.
Tile Graphs Tool
Tiles graphs in the analysis area after changing the size of the analysis area to fit all graphs to the new space.
Layout Tools
Chooses a layout for the IDEAS window.
Building Blocks Tool
Short-cut to using Building Blocks for guided analysis.
Wizards Tool
Short-cut to using Wizards for guided analysis.
Table 2: Analysis Area Tools
Tool Description
2 Select the one or more populations to graph by clicking them. To select more than one population, use the Ctrl key.
The title defaults to the selected population. You can edit the title.
3 In the X Axis Feature drop down menu, select the feature that you want to graph on the X Axis.
4 If you want to change the label for the X axis, edit the text in the X Axis Label field.
The label defaults to the name of the selected feature.
5 If you are creating a scatter plot, select a feature and a label for the Y Axis.
6 Set the scaling for each axis of the graph. (The default is Auto, which allows the application to automatically scale the graph.)
7 To set minimum and maximum values for an axis, select Manual.
8 Select Linear or Log and enter Maximum and Minimum limits.
9 If you selected Log, enter the X > value.
Note: You can scale the X Axis of a graph or the Y Axis of a scatter plot in one of two modes: Linear or Log. The Linear mode is the default.
The Log mode allows you to logarithmically scale a section of the graph or scatter plot. Selecting this mode causes the IDEAS application to perform bi-exponential plotting. The > X value defines the linear portion of the graph as -X through X.
The application plots the values outside of these limits on a logarithmic scale. You can plot negative values as well as positive ones on a logarithmic scale by adjusting the limits.
Take care not to split a population such that it appears to be two separate popula-tions. This splitting is especially likely when negative values exist due to compensa-tion or correccompensa-tions on the imagery. The graph on the left side was plotted on a linear scale; the ones in the center and on the right side were plotted on logarith-mic scales. The graph on the right side split the population because the change from a linear to a logarithmic scale occurred in the middle of the population. The IDEAS application automatically chose 1000 for the scale of the graph that is in the center.
10 To modify the display characteristics of each population or to change the layering order, click Display Properties.
The Display Properties window opens.
11 Arrange the layering of the populations with the up and down arrows to allow them to be displayed.
12 If you want, click Populations... to open the Population Manager. (For more information, see “Using the Population Manager” on page 106.)
13 If you are creating a histogram overlay, you can customize it by performing the following steps:
• To fill or not fill the line for a population, select or clear the Fill checkbox.
• If you want, change the Bin count. (The default is determined by the X Axis scale of the plots.)
• Decide whether to plot the Y Axis Units as a Frequency or a Normalized frequency percentage.
14 Click OK in each window.
Tip: After you have created a graph, you can change its properties by right-click-ing the graph and selectright-click-ing Graph Properties. The same window that you used
to create the graph will reappear, and you can then make any changes that you want.
To show selected statistics for a graph
1 You can show and hide statistics is by clicking the Statistics toolbar button in the panel that contains the graph.
2 Or, right-click anywhere on the graph, and, click Statistics on the graph context menu that appears.
The Statistics window appears.
3 To display the statistics for the graph, select Show statistics. To close the Statistics Area for the graph, select Hide statistics.
4 Select the statistics that you want to display. The selected statistics will be displayed for each population on the graph. (For a complete definition of all the statistics, see
“Using the Statistics Area” on page 87.) 5 When finished, click Close.
To show the legend for a graph
1 Right-click anywhere on the graph, and click Show/Hide Legend on the graph context menu that appears.
If the legend was hidden, it appears on the graph. If the legend was shown, it disap-pears from the display.
Note: The legend contains an entry for each population on the graph. If the graph is a scatter plot, the legend shows the population and its associated point style and color. If the graph is a histogram or overlay histogram, the legend shows the popu-lation name, associated color, and line type.
• To move the legend, click and drag it. (You cannot drag the legend past the boundary of the graph panel.)
Moving a Graph
• With any graph in the Analysis Area, you can move it to another location by clicking in the upper section of the graph and dragging it.