Rolf, many thanks for these suggestions, I will definitely give these a go.
I ended up resorting to locator() to ascertain the x y coordinates I required, 
but obviously this isn't optimal.
Thanks again,Oli

> Date: Thu, 7 Feb 2013 12:38:22 +1300
> From: rolf.tur...@xtra.co.nz
> To: oti...@hotmail.com
> CC: r-help@r-project.org
> Subject: Re: [R] Predictions from the Segmented Package
> 
> 
> 
> Since no-one else seems to have responded to your question, I'll
> chip in with my two bob's worth:
> 
> (1)  You can probably get what you might want to get from predict()
> by looking at X$fitted.values --- where X is the object returned by
> segmented().
> 
> (2) But predict() is probably the wrong way to go.  You can get
> the break points (or point if you have just two segments) by
> looking at X$psi[,2].
> 
> You can get the slopes of the segments from slope(X).  You
> can get the intercepts of the segments from intercept(X).
> 
> This should give you all the information that you need.  Said
> he, optimistically.
> 
> HTH
> 
>      cheers,
> 
>          Rolf Turner
> 
> P. S. Does anyone know why or whither Vito Muggeo has disappeared?
> 
>          R. T.
> 
> On 02/06/2013 11:30 AM, oli tills wrote:
> > Hi,
> > I would like to calculate the area under segmented regression lines (single 
> > breakpoints). I had thought that I could do this using the predict() 
> > function to ascertain some key x y values in order to determine the 
> > dimensions for two trapezoids (under each segment of my regression). 
> > However, I've not had any success with this and have just read online that 
> > the predict function does not work for segmented. Has anyone successfully 
> > done what I describe? Or is able to provide some advice on how best to 
> > approach this task?
                                          
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