Penttinen(r)"interact"
describing the interpoint interaction
structure of a point process.The scale of interaction is controlled by the disc radius $r$: two points interact if they are closer than $2 r$ apart. The strength of interaction is controlled by the canonical parameter $\theta$, which must be less than or equal to zero, or equivalently by the parameter $\gamma = e^\theta$, which must lie between 0 and 1.
The potential is inhibitory, i.e. this model is only appropriate for regular point patterns. For $\gamma=0$ the model is a hard core process with hard core diameter $2 r$. For $\gamma=1$ the model is a Poisson process.
The irregular parameter
$r$ must be given in the call to
Penttinen, while the
regular parameter $\theta$ will be estimated.
This model can be considered as a pairwise approximation
to the area-interaction model AreaInter.
Penttinen, A. (1984)
Modelling Interaction in Spatial Point Patterns:
Parameter Estimation by the Maximum Likelihood Method.
ppm,
ppm.object,
Pairwise,
AreaInter.fit <- ppm(cells ~ 1, Penttinen(0.07))
fit
reach(fit) # interaction range is circle DIAMETERRun the code above in your browser using DataCamp Workspace