Piecewise regression & discriminant analysis(?)

I found what looks like helpful references to piecewise regression. The first is an Ecology paper. The second is a USFS report with SAS code and data that looks like it might be very helpful. Sorry to be redundant if you already have these.

Has there been any thought/work on using some kind of multivariate methods of determining thresholds? I am thinking of something like a discriminant function (linear or nonlinear) that distinguished between groups. If data are available where "states" are identifiable using multivariate datasets (like Mark's data), then a discriminant function may provide some way of determining thresholds among groups using several important variables. I'm thinking back to a class from>5 years ago, but thought I would see if you know whether this has been attempted. I've searched some papers and found some interesting methods from folks in Maryland looking at aquatic systems (Bob Hilderbrand et al.). I've been going through papers from the Duluth DVD, but haven't found such an analysis used yet. But, there's a lot on that DVD.

On other fronts: I've set the blog so that it should be easier to comment. Just use the "anonymous" choice for now until you all sign in and get register with the blog. Make sure to sign your comment so we know who said what.

Looks like Mark and I are scheduled to meet with Sue Phillips on October 20th. She mentioned data that she gave you; Are those the data you're planning on sending me this week?

Thanks,
Travis