R help - Sep 2007 - Calculate the angles for a point dataset?

Dear Rusers,
  I'd like to take the cases of cancer of the larynx in chorley(spatstat) to
explain my question.
  I want to join the points of cancer of the larynx with the disused
industrial incinerator to generate lines, and then calculate the angles of
these line comparing the horizontal line?
  How can i get it? It seems to be difficult to get the angles
  Thanks a lot.

-- 
With Kind Regards,

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Zhi Jie,Zhang ,PHD
Tel:86-21-54237149
Dept. of Epidemiology,School of Public Health,Fudan University
Address:No. 138 Yi Xue Yuan Road,Shanghai,China
Postcode:200032
Email:epistat@gmail.com
Website: www.statABC.com
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On 14/09/2007, at 3:41 PM, zhijie zhang wrote:
> Dear Rusers,
>   I'd like to take the cases of cancer of the larynx in chorley 
> (spatstat) to
> explain my question.
>   I want to join the points of cancer of the larynx with the disused
> industrial incinerator to generate lines, and then calculate the  
> angles of
> these line comparing the horizontal line?
>   How can i get it? It seems to be difficult to get the angles
>   Thanks a lot.
?atan2

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