Finding local minima and maxima of a graph

[Bryan McCormick]

I have a very large number of graphs to crunch through to find local 
minima and maxima. The data is regularly spaced, which eliminated one 
problem. I know too that the window value used has to be an adjustable 
variable as peak and trough significance may need to be found for a wide 
range of time periods within the data set.

I had thought of using a moving average to find a slope of zero and then 
use an offset function to find the peak and trough in time.

I've used stackoverflow to have a look and apparently the problem is a 
lot less trivial than I thought.

Any suggestions for fitting to a function, using the graphing functions 
in rev, etc would be most welcome.