[R-sig-Geo] Simulating raster or spatialgriddataframe images

[Andrew Niccolai]

Greetings,

At the risk of being ridiculed for such a general question, can anyone offer
suggestions or decent code to simulate grid images with specific patterns?
I have been reading R Graphics and I am not sure if a grob will suffice, but
I would like to create a "controlled" circular or rectangular image in which
I can insert a star pattern or a pattern of high valued clumps evenly
distributed around the image.  I am interested in creating these controlled
or simulated images in order to better understand the ability of gstar and
local moran's I statistics in discriminating among image objects with
different internal patterns but that share similar overall averages and
standard deviations.  Can anyone suggest code or techniques inside of R that
will allow me to create a series of SGDF objects that have a specific set of
internal patterns associated with them.

Thanks in advance and I apologize for the "vagueness" of the query.

Andrew Niccolai
Doctoral Candidate
Yale School of Forestry