[R-sig-Geo] spatstat - kppm function

[Adrian Baddeley]

On 07/06/17 09:57, Fernanda De Bastiani wrote:

>Dear Sir/Madam,
>I am trying to use function kppm() of spatstat package with anisotropic
>covariance option as the following:
>#-------------------------------------------
>    kppm(redwood, ~x, "LGCP", statistic="pcf",
>covmodel=list(model="matern",
>nu=0.3, Aniso = matrix(nc=2, c(1.5, 3, -3, 4))))
>#-------------------------------------------
>but it gives me an error message:
>Error in rfInit(model = p, x = x, y = y, z = z, T = T, grid = grid,
>distances = distances,  :
>    'RFcov' :  'Aniso' : not of the required size: (2, 2) instead of
>(undetermined, 1)
>Please, could anyone help me to understand in which conditions nc=2 will
>work?

The kppm() function is designed for models whose pair correlation function
is isotropic.
It cannot be used to fit an anisotropic model.

(Extending this to anisotropic models is conceivable but it would require
new theory as well as completely new software).

I¹m sorry about the opaque error message. I¹ll try to find a way to detect
anisotropic models and give a more meaningful message from the spatstat
code.

Adrian Baddeley