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Interactive Control Charts |
You can specify an WEBOUT= data set in any chart statement to save graphics coordinate information for a control chart. The WEBOUT= data set is an extension of the OUTTABLE= data set, which contains the subgroup summary statistics, control limits and related information found in an OUTTABLE= data set, as well as coordinate data. The additional coordinate variables are listed in Table 50.1.
Table 50.1: WEBOUT= Data SetVariable | Description |
_X1_ | x-coordinate of lower left corner of primary chart subgroup bounding box |
_Y1_ | y-coordinate of lower left corner of primary chart subgroup bounding box |
_X2_ | x-coordinate of upper right corner of primary chart subgroup bounding box |
_Y2_ | y-coordinate of upper right corner of primary chart subgroup bounding box |
_Xn_ | x-coordinate for point n of the subgroup shape |
_Yn_ | y-coordinate for point n of the subgroup shape |
_X1_2_ | x-coordinate of lower left corner of secondary chart subgroup bounding box |
_Y1_2_ | y-coordinate of lower left corner of secondary chart subgroup bounding box |
_X2_2_ | x-coordinate of upper right corner of secondary chart subgroup bounding box |
_Y2_2_ | y-coordinate of upper right corner of secondary chart subgroup bounding box |
_SHAPE_ | shape of primary chart subgroup bounding area |
_NXY_ | number of points defining primary chart subgroup bounding area |
_GRAPH_ | name of primary chart graphics entry |
_GRAPH2_ | name of secondary chart graphics entry |
_DXMIN_ | value of lowest major tick mark on horizontal axis |
_DXMAX_ | value of highest major tick mark on horizontal axis |
_XMIN_ | x-coordinate of lowest major tick mark on horizontal axis |
_XMAX_ | x-coordinate of highest major tick mark on horizontal axis |
_DYMIN_ | value of lowest major tick mark on vertical axis |
_DYMAX_ | value of highest major tick mark on vertical axis |
_YMIN_ | y-coordinate of lowest major tick mark on vertical axis |
_YMAX_ | y-coordinate of highest major tick mark on vertical axis |
_XMIN2_ | x-coordinate of lowest major tick mark on secondary chart horizontal axis |
_XMAX2_ | x-coordinate of highest major tick mark on secondary chart horizontal axis |
_DYMIN2_ | value of lowest major tick mark on secondary chart vertical axis |
_DYMAX2_ | value of highest major tick mark on secondary chart vertical axis |
_YMIN2_ | y-coordinate of lowest major tick mark on secondary chart vertical axis |
_YMAX2_ | y-coordinate of highest major tick mark on secondary chart vertical axis |
You can use the coordinate data saved in the WEBOUT= data set to create a "clickable" control chart in a SAS/AF application. The variables _X1_, _Y1_, _X2_ and _Y2_ contain the coordinates of the lower left and upper right corners of a rectangular bounding box associated with each subgroup on the primary chart. This box defines the clickable area associated with the subgroup when the chart is incorporated into a SAS/AF application. It contains the symbol used to plot the subgroup data, or the junction of line segments representing the subgroup if no plotting symbol is used. The variables _X1_2_, _Y1_2_, _X2_2_ and _Y2_2_ contain coordinates of the corners of subgroup bounding boxes for a secondary chart.
If you use the BOXCHART statement, each subgroup is represented by a box-and-whisker plot rather than a single symbol. The subgroup's bounding box is defined by the sides of the box-and-whisker plot and its lower and upper quartiles, regardless of the BOXSTYLE= value in effect.
If you specify the STARVERTICES= option, each subgroup is represented by a polygon or star with a vertex corresponding to each of the STARVERTICES= variables. The clickable area for a subgroup is the polygon with these vertices, regardless of the STARTYPE= value specified. In the WEBOUT= data set the value of the _SHAPE_ variable is POLY and the _NXY_ variable contains the number of vertices in the polygon. The variables _Xn_ and _Yn_, where n = 1 to the value of _NXY_, contain the coordinates of the vertices of a subgroup's polygon. When the STARVERTICES= option is not used, the value of _SHAPE_ is always RECT and the value of _NXY_ is always 2.
When a control chart spans multiple panels (pages), the panels reside in separate SAS graphics entries. The _GRAPH_ character variable records the name of the graphics entry containing the panel on which a given subgroup is plotted. This is the same name that appears in the PROC GREPLAY menu. When the SEPARATE option is used, primary and secondary charts are displayed on different graphics entries. The _GRAPH2_ variable records the name of the graphics entry containing the secondary chart panel where a subgroup appears. When the SEPARATE option is not used, the values of _GRAPH_ and _GRAPH2_ will be the same for a given subgroup.
The variables _DXMIN_, _DXMAX_, _XMIN_ and _XMAX_ provide the data values and graphics coordinates associated with the lowest and highest major tick marks on the horizontal (subgroup) axis. The variables _DYMIN_, _DYMAX_, _YMIN_ and _YMAX_ provide the analogous values for the vertical axis. Through a simple linear transformation in your SAS/AF application you can use this information to convert from percent screen units to "data" units and vice versa.
The variables _XMIN2_ and _XMAX2_ contain the graphics coordinates associated with the lowest and highest major tick marks on the horizontal axis of a secondary chart. No variables for the corresponding data values are required, since they are always identical to those for the primary chart.
The variables _DYMIN2_, _DYMAX2_, _YMIN2_ and _YMAX2_ contain the data and coordinate values for the lowest and highest tick marks on the vertical axis of a secondary chart. A SAS/AF program receives the (x,y) coordinates for the location of the cursor when the user clicks on a subgroup data point. The application can determine whether (x,y) lies within any of the boxes whose coordinates are saved in the WEBOUT= data set. If so, the program can determine which subgroup was selected on the primary or secondary chart and can check the _TESTS_ and _TESTS2_ variables included in the WEBOUT= data set to determine whether an out-of-control condition has been signaled.
Notes:
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