Why are there gaps on the heat map that cannot be deleted

[Kjnmy]

Dear friends：
I am using ggplot2 to draw a heat map, but when the time variable is used as the horizontal axis, there is always a white gap as shown in the figure below. I have tried various methods but cannot delete it.
I earnestly request your guidance, thank you.

plotda <- xd[dtime<=as.Date('1962-3-1'),]
ggplot(plotda,aes(x=dtime,y=station,fill=severity))+
  geom_tile()+
  facet_grid(group~. )+
  scale_x_date(expand=expansion(mult=0,add=0),minor_breaks=NULL,date_labels='%Y%m')

[nirgrahamuk]

I'd try changing panel spacing to zero by adding

+ theme(panel.spacing = unit(0,"cm"))

[Kjnmy]

Thank you very much for your answer, but multiple vertical gaps still exist.

[nirgrahamuk]

for further assitance please provide a reprex

FAQ: How to do a minimal reproducible example ( reprex ) for beginners

A minimal reproducible example consists of the following items: A minimal dataset, necessary to reproduce the issue The minimal runnable code necessary to reproduce the issue, which can be run on the given dataset, and including the necessary information on the used packages. Let's quickly go over each one of these with examples: Minimal Dataset (Sample Data) You need to provide a data frame that is small enough to be (reasonably) pasted on a post, but big enough to reproduce your issue. Let's say, as an example, that you are working with the iris data frame head(iris) #> Sepal.Length Sepal.Width Petal.Length Petal.Width Species #> 1 5.1 3.5 1.4 0.…