processing GPS track data?

Hi all,

I have a set of GPS track data (in .gpx format now) that I need to
process, and I'm hoping to use R to do it. I've been using R for a
number of years now, but this is my first time wading into spatial
data.

Specifically, I need to:
   1) Smooth the tracks
   2) Select random locations along the tracks
   3) Select segments of the tracks, corresponding to the random locations
   4) Check for overlap between the segments
   5) Output the random segments, preserving other track attribute
data (e.g., timestamps)

So far, my searches on r-sig-geo have come up negative. Has anyone
dealt with data like this before? Can someone recommend the
appropriate packages/functions? PostGIS sounds like it may be another
option if R doesn't yet have the packages.

Thanks for your help.

Regards,
Malin

Malin Pinsky
Ph.D. Candidate, Palumbi Lab
Hopkins Marine Station
Stanford University
Pacific Grove, CA  93950
mpinsky at stanford.edu