On Tue, Mar 4, 2014 at 1:47 AM, Rolf Turner <r.turner@auckland.ac.nz> wrote:

>
>
> Questions:
> ==========
>
>
> (2) Even if there are no such functions, is there anything intrinsically
> *wrong* with having a function possessing this somewhat schizophrenic
> nature?  Is it likely to cause confusion, induce syntactical mistakes,
> create errors, or produce wrong results?
>
> Any thoughts, comments, insights or suggestions gratefully received.
>


 I don't see why you can't conceptually think of w = owin(some_ppp_object)
as an owin "Constructor" rather than an "Accessor". Its "constructing" (and
returning) an owin from an object, it just happens to be as simple as
getting a component from that object.

 The raster package has the 'extent' function - you can create an extent
with extent(xmin,xmax,,,etc), get the extent of a raster with extent(r), or
set the extent of a raster with extent(r1) <- extent(r2), so I don't see
any problem with:

w1 = owin(poly=...) # construct polygon owin

ppp1 = ppp(x,y,window=w1)
ppp2 = ppp(x,y, window=owin(ppp1)) # construct window from ppp object

owin(ppp1) = owin(ppp2)  # give ppp1 the owin of ppp2

That all reads pretty nicely. As long as owin(...) returns an observation
window and owin<-(...) assigns an observation window to an object that can
validly have one, I don't think you can go wrong. I've probably already
tried to do "owin(ppp1)=..." a few times...

Barry

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