Version 2.3.0 of ‘secr’ now on CRAN has new capability for density surfaces as described in a vignette (see secr-densitysurfaces.pdf, accessed via ?secr from R once package loaded). Users may define their own surface model as an R function, and functions ‘predictDsurface’, ‘plot.Dsurface’ and ‘spotHeight’ make for easy plotting. ‘addCovariates’ simplifies the extraction of spatial covariates from another spatial data source for use in a density model.
See the NEWS link at http://cran.r-project.org/web/packages/secr/ for other new features and bug fixes. From 2.3.0, fitted model objects do not include predicted densities (component D).