[R] readable dendrograms with many units

[Paul Slater]

Using Mathematica, I've performed a hierarchical clustering
of 3,107 U. S. counties based on 1995-2000 intercounty
migration, using an algorithm of my own devising
(see http://arxiv.org/abs/0807.1550). I can also generate
the associated 3,107 x 3,107 matrix of ultrametric distances.

Unfortunately, as far as I have been able to
determine, the Mathematica hierarchical clustering
package only produces readable dendrograms with twenty-or-so
or fewer units.

So, I'm wondering whether I can be more successful in looking at
my clustering results overall with R (which
I have not previously used). Please note that I'd rather not have to
produce a hierarchical clustering from scratch using one of the more
standard methodologies (single, complete linkage,...). So, I might
have to use the (non-sparse) 3,107 x 3,107 matrix of ultrametric
distances as an input distance matrix.

Thanks for any suggestions/information...,


Paul B. Slater