[R-sig-Geo] qqplot.ppm

[Adrian Baddeley]

Tom_R <tom.richardson at bristol.ac.uk> writes:

> I am attempting to obtain a qqplot for a ppm 

This is in the package 'spatstat'.

> The object is a Geyer model ('Hard0'). The 'Saturation' and 'Interaction
> range' parameters for the Geyer model are obtained   using profile
> log-likelihood ('profilepl').

> I am using a spatial covariate (Z) which is a pixel image (dens_all). This
> covariate is causing problems for qqplot.ppm. I am getting the following
> error from qqplot.ppm; "ERROR : Error in rmhResolveExpansion(win, control,
> covims, "covariate") : 
>   Cannot expand the simulation window, because the covariate images do not
> cover the expanded window". 

First, I suggest you upgrade to the latest version of spatstat (1.20-3) and check whether this
problem still occurs. 

If it is still occurring, then in the call to qqplot.ppm you need to add the argument 'control'
described in help(qqplot.ppm) or help(rmhcontrol). Set control$expand = 1 so that no expansion of the simulation window occurs. For example:

    qqplot.ppm(Hard0, fast=TRUE, plot.it=FALSE, nsim=39, control=list(nrep=1e5, expand=1))

Use nsim=39 to get 5% significance bands.

Adrian Baddeley