我正在使用该mgcv包根据一些环境协变量对臭氧污染浓度进行建模。该模型采用以下形式：
model1 <- gam(O3 ~ s(X, Y, bs = "tp", k = 10) + wd + s(date, bs = "cc", k = 100) + district,
data = mydata, family = gaussian(link ="log"),
na.action = "na.omit", method = "REML")
这是协变量的结构：
> str(mydata)
'data.frame': 7100 obs. of 286 variables:
$ date : Date, format: "2016-01-01" "2016-01-01" "2016-01-01" ...
$ O3 : num 0.0141 0.0149 0.0102 0.0159 0.0186 ...
$ district : Factor w/ 10 levels "bc","bh","dl",..: 1 8 7 8 …