如何使用ggplot2从geom_tile（热图）中删除白线

Question

我在热图中删除瓷砖之间的白线时遇到问题。下面是我的代码和图片。有没有人遇到过这个？

t <- ggplot(Drug_heatmap_df_final, 
   aes(x=reorder(Drug,Total_Deaths), y=Start_Date, fill=Total_Deaths)) + 
   geom_tile() + 
   labs(title="Heatmap of Total Deaths per month by Drug", x="Drug", y="Month") + 
   theme(plot.title = element_text(hjust=.5)) +
   scale_y_date(date_breaks="1 year" , labels = date_format("%b-%Y")) +
   theme(axis.text.x = element_text(size=13)) 

plot(t)

Answer 1

因此，我为同样的问题而苦苦挣扎，无法使犯罪轴（24小时周期）离散。最后，我意识到我每2分钟（一小时的1/30）绘制图块的位置，我的csv数据文件将这些点四舍五入至0.03的间隔，在图块之间留有空隙，因此出现了白线。我只是将excel工作表中的小数位数从2更改为许多，给出了0.03333333的间隔，白线消失了。霍雷！ my heatmap before vs after

Answer 2

I don't know if this is the most elegant solution but if you add color in your aes and then play with the size in geom_tile you can get them to overlap and remove the white lines:

First is how my data looks with the white lines:

ggplot(mydf, aes(x=grp, y=date, fill=n)) + 
  geom_tile()

Now I set my color to the same object as my fill and mess with the size:

ggplot(mydf, aes(x=grp, y=date, fill=n,color=n)) + 
  geom_tile(size=0.6) 

Like I said, probably not the most elegant solution, and there is probably a better, more efficient way to determine the size value (instead of trial and error like I did) but in general this seems to solve your issue.