If your Annotate data set
specifies a coordinate system that is based on data values (that is,
XSYS, YSYS, and HSYS are assigned the values 1, 2, 7, or 8), the data
values determine the size and location of the graphics elements on
the output.
If the procedure that
specifies the annotation generates axes (such as GPLOT or GCHART),
by default the axes are scaled to accommodate the full range of data
values and to fit in the procedure output area. Because all values
are included in the axes, the graph displays all the Annotate output
that is dependent on data values.
However, if the annotation
displays with the GSLIDE or GANNO procedure, which do not generate
axes, the data values might generate coordinate values that exceed
the limits of the graphics output area.
In this case, you can
use the DATASYS option to tell the procedure that the Annotate data
set contains data-dependent coordinates and to scale the output accordingly.
For an illustration of this process, see
Scaling Data-Dependent Output.
When you use the DATASYS
option, the GANNO procedure reads the entire input data set before
drawing the graph and creates an output environment that is data dependent.
That is, the environment is based on the minimum and maximum values
that are contained in the data set. It then scales the data to fit
this environment so that all graphics elements can be drawn.
Although the DATASYS
option enables you to generate graphs using one of the data-dependent
coordinate systems, it requires that the procedure scan the entire
data set to determine the minimum and maximum data values. You can
save this extra pass of the data set by using data-dependent values
only in procedures that generate axes. Annotate coordinate system
5 (percent of the procedure output area) is recommended for use with
the GANNO procedure. This coordinate system works equally well with
the GSLIDE procedure if you decide to display the annotation with
titles and footnotes.