Here is an example script that adds an annotation line to the graph. I simply used the annotation tools to draw the line, and then captured the script.
Names default to here(1);
dt=open("$SAMPLE_DATA\big class.jmp");
Graph Builder(
Size( 587, 495 ),
Variables( X( :weight ), Y( :height ), Group Y( :sex ) ),
Elements( Points( X, Y, Legend( 7 ) ) ),
SendToReport(
Dispatch( {}, "height", ScaleBox, {Min( 56.9527534300518 )} ),
Dispatch(
{},
"",
GraphBuilderContainerBox,
Add Line Annotation(
Line( {52, 251}, {550, 249} ),
Color( "Black" ),
Thick( 1 )
)
)
)
);
Jim