Is a point into an ellipse

2 messages · Alain Guillet, Duncan Murdoch

Wed, Apr 8, 2009 8:17 AM #

Hi,

I drew an ellipse with the package ellipse. Now I would like to know  if 
a point is inside the ellipse. Is any R functions to do it without 
computing the equation of the ellipse manually? Thanks.

For example, if I do "plot(ellipse(0.8), type = 'l')", I would like to 
know if (0,1) belongs to the drawn ellipse.


Regards,
Alain

Alain Guillet
Statistician and Computer Scientist

SMCS - Institut de statistique - Universit? catholique de Louvain
Bureau d.126
Voie du Roman Pays, 20
B-1348 Louvain-la-Neuve
Belgium

tel: +32 10 47 30 50

Duncan Murdoch

Wed, Apr 8, 2009 9:02 AM #

On 4/8/2009 11:17 AM, Alain Guillet wrote:

It's probably too late by then, but if you saved the result of the call 
to ellipse(0.8), and treat it as a polygon, there is the function 
point.in.polygon in the sp package, or pip in splancs, or inside in 
RFOC, or inside in GEOmap, etc.

Duncan Murdoch