Generalized additive models: Plots for Qualitative Data

Hello,
My name is Dontrece Smith. I am creating figures for my GAMs. I change my
qualitative variables to 1 or 2 in my dataset, so I would be able to run my
GAMs. However, R will only display plots for my quantitative variables and
not my qualitative variables. Is there any way to fix this issue? I listed
some of my code below:

library(mgcv)

This is mgcv 1.7-13. For overview type 'help("mgcv-package")'.

Final <- read.csv("Final.csv", header=TRUE)
gam4<-gam(Bonnet ~ s(Depth, bs="cs", k=4) + s(Distance, bs="cs", k=4) +

s(Width, bs="cs", k=4) + as.factor (System) + as.factor(Channel) +
as.factor (Profile)  + s(Slope, bs="cs", k=4), data = Final)

plot(gam4, shade=TRUE, pages=1)