[R] invalid type (list) for variable

Hello - I am attempting to add interaction terms to a model using the gamm function in the mgcv package. I stripped it down to only two terms to simplify it. I have no trouble with individual terms, continuous or factors, nor with interacting factor terms; I cannot, however, figure out how to add

[R] R package for visualizing/analyzing accelerometry data?

Hello All - Any recommendations or suggestions for neat ways to visualize data taken from a 3-axis accelerometer? My study species is aquatic, so I would be interested in movement in the 3 dimensions in addition to being able to incorporate the time series as well. Is there a package in R that mig