overlay several graphs
-----------------------

^overlay^ , ^by(^varlist^)^  ^xlab(^numlist^)^ ^ylab(^numlist^)^ ^function(^str
> ing^)^ 
   ^saving(^filename^)^ ^graph_options^

Description
-----------

This function draws several graphs in one area of the graphics window. As a res
> ult this
function is very versatile and will work well with any graph function that allo
> ws
the user to specify the axes. The function will, by default,  
try and calculate an axes that remains unchanged for each graph, this may fail 
> and the
user then has to specify the axes using ^xlab^ and ^ylab^.

Any options for the graphing function can be added to the end of the command li
> ne. 
This can be options like the plotting symbol and connecting points.

WARNING: to get the same scales make sure you specify the
xlab and ylab options and hence this should fix the axes.

Options
-------

^by(^varlist^)^  specifies the strata for the multiple graphs.

^saving(^filename^)^ saves the graph as filename.gph.

^function(^string^)^ specifies the command that draws the graph. If this
is not specified then the {\tt graph} function is used.

^xlab(^numlist^)^ specifies axes labels.

^ylab(^numlist^)^ specifies axes labels.

Examples
--------


.overlay pef day0, by(patient) c(l) s(.) sort saving(graph1)


.overlay pef if patient<5028, by(patient) function(kdensity) xlab(150,350,680) 
ylab(0,0.02, 0.045) s(.) saving(graph3)

.overlay pef if patient<5028, by(patient) xlab(150,350,680) bin(8) ylab(0,1.1)

If the user wants to have fitted lines from a regression with confidence intera
> vals 
for several subgroups

.overlay yhat yhatupper yhatlower x, by(subgroups) c(ll[-]l[-].) s(iiio)

Author
------
   Adrian Mander
   GSK, Harlow UK.
   adrian.p.mander@gsk.com

Also see
--------

 Manual:  ^[R] kdensity^
On-line:  help for @kdensity@, @graph@