{smcl}
{* 6may2004}{...}
{hline}
help for {hi:circqqplot}
{hline}

{title:Quantile-quantile plot for circular data}

{p 8 17 2}
{cmd:circqqplot} 
{it:varname1} {it:varname2} 
[{cmd:if} {it:exp}] 
[{cmd:in} {it:range}]
{cmd:,} {cmd:centre(}{it:#1} [{it:#2}]{cmd:)} 
[{cmd:yshow(}{it:numlist}{cmd:)}
{cmd:xshow(}{it:numlist}{cmd:)}
{cmd:plot(}{it:plot}{cmd:)}
{it:qqplot_options}] 


{title:Description}

{p 4 4 2}
{cmd:circqqplot} gives a quantile-quantile plot for two circular variables on a
scale between 0 and 360 degrees. Note that the variables are not paired and do
not even have to be non-missing for the same observations. Both variables are
rotated so that each set of values is centred on a specified value.  Each is
nevertheless labelled in terms of the original variables. 


{title:Options}

{p 4 8 2}{cmd:centre()} is a required option. With one argument, 
it specifies a centre to be used for both variables. With two 
arguments, it specifies two centres to be used for the first 
and second variable respectively. The spelling {cmd:center()} is 
indulged. 

{p 4 8 2} 
{cmd:yshow()} specifies a numlist of {it:y} axis labels to be shown, 
overriding the default.

{p 4 8 2} 
{cmd:xshow()} specifies a numlist of {it:x} axis labels to be shown, 
overriding the default.

{p 4 8 2}
{cmd:plot(}{it:plot}{cmd:)} provides a way to add other plots to the generated
graph; see help {help plot_option}.

{p 4 8 2} 
{it:qqplot_options} are any options allowed with {help diagplots:qqplot}.  


{title:Examples}

{p 4 4 2}{cmd:. circqqplot axisasp wallasp, centre(45)} 


{title:Author}

{p 4 4 2}Nicholas J. Cox, University of Durham, U.K.{break} 
         n.j.cox@durham.ac.uk


{title:Also see}

{p 4 13 2}
On-line: help for {help circqvm}, {help diagplots}