help tp select points of border with spatstat

I have a points shapefile with wave shape. I wish to select only the border
points to create a border owin with the same wave shape. I tryed to use
convex.hull but the final shape is not the same. Some researchers have some
suggestions?

I once had a similar issue when I wanted to create a hull (i.e. select
only the border points) for a non-convex set of points, so-to-say. I ended
up doing some approximation and also came across the alphahull package.
Maybe "ahull" in that package with a suitable "alpha" parameter can help.

Georg.

Research Assistant
Otto-von-Guericke-Universit?t Magdeburg
research at georgruss.de
http://research.georgruss.de