Additions to r.mdig.kernel

[Joel Pitt]

Hi Steve,

I recently added the following options to the kernel module to address
the use-case you had:

-c Conserve individuals - events redistribute individuals rather
than create new ones
-m Convert values that are less than 1 to NULL.
-p Make frequency dependent on population/value (population is
multiplied by freq option).

----
So you'll want -c to conserve individuals.

-m might be needed to ensure cells with less than one individual get
converted to NULL cells (depends on what type of map you are using,
generally you'll want this though...)

-p means that you can make the freq option a multiplier for the number
of individuals. If you set freq=1 and use -p, then you'll generally
get all individuals dispersed, although it currently still uses the
Poisson distribution to work out how many dispersal events to do.

Cheers,
J