SAS/AF Software: Class Dictionary

Using Subsets of Data in a Chart Control

To create subsets of the data for a Chart control, you can:

Use the dataSetID attribute when specifying data for the analysis. This technique lets you use a WHERE clause to create a data subset before displaying a graph. For more information, see Specifying Data in a Chart Control.
Provide reference lines so the user can interactively position the reference line at data points of interest. You can then query the reference lines to get their position, and create a data subset using those data values. For information on using reference lines, see Adding Reference Lines to a Chart Control.

Because you can query a reference line for its position, you can create an application that creates data subsets interactively. In this application, the user can drag the reference lines to encompass the data range of interest. You can then query each line to determine its position, and generate a graph that uses those position values as the minimum and maximum values in the analysis.

For example, assume you have added two reference lines to a control named chart1, and that you stored their ID's in the variables refLine1 and refLine2. The following code queries the lines for their values and sets the data source for a histogram whose lowest data value is the value from line refLine1, and whose highest value is the value from line refLine2:

lowVal=0;
highVal=0;
chart1._getReferenceLineValue(refLine1, lowVal);
chart1._getReferenceLineValue(refLine2, highVal);
/* open a data set and use the reference-line */
/* values as the low and high values          */
dsid=open('sasuser.mydata');
   rc=where(dsid, 'x>lowVal','and x<highVal');
/* assume hist1 is an existing Histogram control */
hist1.dataSource='datasetid';
hist1.dataSetID=dsid;

Chapter Contents
Previous
Next
Top of Page