Figure 1. GPL for line chart with step interpolation
* Open sample file Employee Data.sav.
GGRAPH
/GRAPHDATASET NAME="graphdataset" VARIABLES=salbegin salary
/GRAPHSPEC SOURCE=INLINE.
BEGIN GPL
SOURCE: s=userSource(id("graphdataset"))
DATA: salbegin=col(source(s), name("salbegin"))
DATA: salary=col(source(s), name("salary"))
GUIDE: axis(dim(2), label("Current Salary"))
GUIDE: axis(dim(1), label("Beginning Salary"))
ELEMENT: line(position(smooth.step.center(salbegin*salary)))
END GPL.
Figure 2. Line chart with step interpolation