[R] error in plots of gam (package:gam)

[Chris.Taylor at noaa.gov]

(Sorry for the duplicate posting, first posting did not contain text in the body of the message.)

Greetings,
I am attempting to plot the model fits of a generalized additive model using the gam package (gam version 1.0, R v. 2.6.2).  The gam object is created without any apparent problem, but when I try to plot (plot(<gam_object>)), I repeatedly receive the following error: "Error in dim(data) <- dim : attempt to set an attribute on NULL".  Diagnostics are pasted below.  Cheers,  Chris Taylor

>Traceback()
14: array(np, 1)
13: predict.gam(object, type = "lpmatrix", ...)
12: model.matrix.gam(object)
11: model.matrix(object)
10: predict.lm(object, newdata, se.fit, scale = residual.scale, type = ifelse(type ==
        "link", "response", type), terms = terms, na.action = na.action)
9: predict.glm(object, type = "terms", terms = terms, se.fit = TRUE)
8: NextMethod("predict")
7: switch(type, response = {
       out <- predict.gam(object, type = "link", se.fit = TRUE,
           ...)
       famob <- family(object)
       out$se.fit <- drop(out$se.fit * abs(famob$mu.eta(out$fit)))
       out$fit <- fitted(object)
       out
   }, link = {
       out <- NextMethod("predict")
       out$fit <- object$additive.predictors
       TS <- out$residual.scale^2
       TT <- ncol(object$var)
       out$se.fit <- sqrt(out$se.fit^2 + TS * object$var %*% rep(1,
           TT))
       out
   }, terms = {
       out <- NextMethod("predict")
       TT <- dimnames(s <- object$smooth)[[2]]
       out$fit[, TT] <- out$fit[, TT] + s
       TS <- out$residual.scale^2
       out$se.fit[, TT] <- sqrt(out$se.fit[, TT]^2 + TS * object$var)
       out
   })
6: predict.gam(object, type = "terms", terms = terms, se.fit = TRUE)
5: predict(object, type = "terms", terms = terms, se.fit = TRUE)
4: preplot.gam(x, terms = terms)
3: plot.gam(Cr4Rot1_100m.gam, se = T, residuals = T, main = "Trend analysis on ABC, 100m resolution: Cr4Rot1")
2: plot(Cr4Rot1_100m.gam, se = T, residuals = T, main = "Trend analysis on ABC, 100m resolution: Cr4Rot1")
1: plot(Cr4Rot1_100m.gam, se = T, residuals = T, main = "Trend analysis on ABC, 100m resolution: Cr4Rot1")

> sessionInfo()
R version 2.6.2 (2008-02-08)
i386-pc-mingw32

locale:
LC_COLLATE=English_United States.1252;LC_CTYPE=English_United States.1252;LC_MONETARY=English_United States.1252;LC_NUMERIC=C;LC_TIME=English_United States.1252

attached base packages:
[1] splines   stats     graphics  grDevices utils     datasets  methods   base    

other attached packages:
[1] gstat_0.9-47 rgdal_0.5-25 sp_0.9-25    gam_1.0      akima_0.5-1

loaded via a namespace (and not attached):
[1] grid_2.6.2      lattice_0.17-10 mgcv_1.4-1      tools_2.6.2 

-- 
J. Christopher Taylor, Ph.D.
Applied Ecology and Restoration Research
National Ocean Service / NOAA
National Centers for Coastal Ocean Science
Center for Coastal Fisheries and Habitat Research
101 Pivers Island Road, Beaufort, North Carolina 28516-9722
Ph:(252) 838 0833 Fx:(252) 728 8784
Website: http://www.ccfhr.noaa.gov/