R help - May 2008 - How to adaptively sample a simulated population of individuals

Hello,
I am looking for advice on how to adaptively sample from a simulated population.

I have simulated a population of individuals in a matrix and need to do the
following:

1) select a random sample from that population
2) apply a function to that sample to determine if I detect any individuals at
each of the referenced site locations [i,j] in the matrix

3) then if I detect any individuals after that first function (adaptive
condition y[i,j] > 0) I need to sample the 4 adjacent plots in that matrix
[i,j+1]; [i,j-1]; [i+1,j]; [i-1,j]

4) apply that function to those adjacent plots to see if I detect any
individuals
5) continue in that fashion to eventually develop a network

I have already simulated the population with spatial dependence (used a
gamma-poisson mixture), so that in each [i,j] site there is a number of
individuals such that the the adjacent sites (contained in a 4x3 sub-matrix) are
distributed via the same lambda from a poisson distribution, but each 4x3
sub-matrix has a unique lambda describing the distribution.  I have then been
able to sample from that population using the sampling package and have been
able to apply the function to determine if I detect any individuals.

The real problem is how to adapt the sampling protocol to the adjacent plots in
the matrix given I have initially detected an individual.  I am not sure what
the best approach is to do this.  I have thought that because I have the
population simulated in a matrix I already have spatially referenced information
about the population through the [i,j] locations in the matrix, but am not sure
if this is enough spatially referenced information and if it is how do I apply
the function to the adjacent sites.  An alternative would be to assign spatial
coordinates to the sites so that they are referenced or put it into a data.frame
that would keep the locations and the numbers of individuals at each of those
locations.  I am not sure if this is possible ( I am guessing it is) and if so
how to do it.

Any advice on how to do this or where to start would be greatly appreciated.  

Thank you very much,
Krishna 

Krishna Pacifici
Ph.D. Student
Georgia Cooperative Fish and Wildlife Unit
Warnell School of Forestry and Natural Resources
University of Georgia
Athens, GA 30602
(706) 248-9968