Message-ID: <5045537E.8020802@xtra.co.nz>
Date: 2012-09-04T01:03:58Z
From: Rolf Turner
Subject: adding points to a point pattern
In-Reply-To: <!&!AAAAAAAAAAAYAAAAAAAAANurYWtafkREnWeH4rBeYRHigQAAEAAAAHJnoiMpnLhBkCXM6i5hLe8BAAAAAA==@gmail.com>
On 04/09/12 11:58, Frederico Mestre wrote:
> Hello all:
>
>
>
> Is there any way to add points to a point pattern, while keeping a given
> minimum distance amongst this new points and the pre-existing points?
>
Presumably this is a question about the "spatstat" package.
If so, the answer is "yes". At least two ways:
(1) Using rmh() --- need to specify "beta" (the "chemical" activity
parameter). E.g.
# Generate a "test pattern" to which to add points.
set.seed(42)
X <- rSSI(0.05,100)
# Add points.
M <- rmhmodel(cif="hardcore",par=list(beta=300,hc=0.05))
Y <-
rmh(M,start=list(x.start=X),expand=1,control=list(x.cond=as.data.frame(X)))
plot(Y,main="Pattern with points added via rmh")
plot(X,add=TRUE,chars=20,cols="red")
print(min(nndist(Y)))
(2) Using rSSI() --- need to specify the *total number* of points
desired. E.g.
# Add points to the same "test pattern", in a different way.
Z <- rSSI(0.05,npoints(X)+42,x.init=X)
plot(Z,main="Pattern with points added via rSSI")
plot(X,add=TRUE,chars=20,cols="red")
print(min(nndist(Z)))
HTH
cheers,
Rolf Turner