分类轴到连续ggplot

Question

I am trying to create a heat map, where each tile is a month. If I use the dates as a data date type, I get lines over my image that are not acceptable.

So my solution has been to to treat the date as a factor

The problem is that the axis is not presentable. Is there a way to merge the two plots with the x axis from the first plot, but the tiles from the second plot?

ggplot(df, aes(x    = factor(Var2),
           y    = factor(desc(Var1)),
           fill = value)) +

As a reproducible example:

df <- read.table("","Var1","Var2","value","Col"
                 "1",2001-01-31,2001-01-31,-0.0118511587908436,"blue"
                 "2",2001-02-28,2001-01-31,0,"white"
                 "3",2001-03-30,2001-01-31,0,"white"
                 "4",2001-04-30,2001-01-31,0,"white"
                 "5",2001-05-31,2001-01-31,0,"white"
                 "6",2001-06-29,2001-01-31,0,"white")

ggplot(dff, aes(x   = factor(Var2),
           y    = factor(desc(Var1)),
           fill = Col)) +
  geom_tile() +
  scale_x_discrete(breaks=pretty(p$Var2)) 

Output from example

Answer 1

Use dates but manually remove the grid. You can do it by adding + theme(panel.grid = element_blank()) to the plot.