Dear,

I am trying to get a prediction of my GAM on a response type. So that I
eventually get plots with the correct values on my ylab.
I have been able to get some of my GAM's working with the example shown
below:
*
model1<-gam(nsdall ~ s(jdaylitr2), data=datansd)
newd1 <- data.frame(jdaylitr2=(244:304))
pred1 <- predict.gam(model1,newd1,type="response")*

The problem I am encountering now is that I cannot seem to get it done for
the following type of model:

*model3<-gam(y_no~s(day,by=mapID),family=binomial, data=mergeday)*

My mapID consists of 8 levels of which I get individual plots with *
plot(model3)*. When I do predict with a newdata in it just like my first
model I need all columns to have the same amount of rows or else R will not
except it ofcourse, the col.names need to at least include day and mapID.
This way I can not get a prediction working for this GAM, I am confused
because of this part in the model: *s(day,by=mapID).

*I have been reading through the GAM, an introduction with R book from Wood,
S. but could not find anything about predictions with BY in the model.

I hope someone can help me out with this,

Sincerely yours,

Robbert Langenberg

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