Hi Joris, We're using mgcv.
We have data on abundance of groupers on line transects that have the same legth. My coworker has selected a bunch of variables and he has calculated them in terms of total area in different sizes of buffers around the centroid of the transect. He has run gam models (quasipoisson, mgcv) for each explanatory variable at each size of buffer. Then he has selected the signifficant variables. Some variables explain a higher percentage of deviance at different sizes of buffers. And now he wants to build a gam model trying the different explanatory variables but using the values that correspond to the size of the buffer where they explain a higher deviance, so one variable might have the values of a smaller scale whereas other might correspond to a higher buffer size (I don't know if I made myself clear). I am wondering if this is correct. Also I don't know if he should include an offset in spite all the transects have the same length. I'm in charge of looking at the spatial correlation once he builds the model. I don't know much about it but I was thinking of doing a Moran test, correlogram and variogram and then if there's spatial autocorrelation doing gamm, sar or gee. Thanks, Lucia -- View this message in context: http://r.789695.n4.nabble.com/offset-in-gam-and-spatial-scale-of-variables-tp2222483p2222976.html Sent from the R help mailing list archive at Nabble.com. ______________________________________________ R-help@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code.
