网格格式的R ggplot图geom_points

Question

R和ggplot专家， 我开始学习R并尝试ggplot。

我有一个用例，如下所述。

可复制的R代码：

require(ggplot2)
library(ggrepel)

# Create the data frame.
sales_data <- data.frame(
  emp_name = rep(c("Sam", "Dave", "John", "Harry", "Clark", "Kent", "Kenneth", "Richard", "Clement", "Toby", "Jonathan"), times = 3), 
  month = as.factor(rep(c("Jan", "Feb", "Mar", "Jan", "Feb", "Mar", "Jan", "Feb", "Mar", "Jan", "Jan"), times = 3)),
  dept_name = as.factor(rep(c("Production", "Services", "Support", "Support", "Services", "Production", "Production", "Support", "Support", "Support", "Production"), times = 3)), 
  revenue = rep(c(100, 200, 300, 400, 500, 600, 500, 400, 300, 200, 500), times = 3),
  status = rep(c("Low", "Medium", "Medium", "High", "Very High", "Very High", "Very High", "High", "Medium", "Medium", "Low"), times = 3)
)

sales_data$month <- factor(sales_data$month, levels = c("Jan", "Feb", "Mar"))
month_vector <- levels(sales_data$month)
sales_data$month <- as.integer(sales_data$month)

sales_data$status <- factor(sales_data$status, levels = c("Low", "Medium", "High", "Very High"))

dept_vector <- levels(sales_data$dept_name)
sales_data$dept_name <- as.integer(sales_data$dept_name)

ggplot(sales_data, aes(x = month, y = dept_name)) +
  geom_raster(data = expand.grid(sales_data$month, sales_data$dept_name),
              aes(x = Var1, y = Var2, width=1, height=1), fill = NA, col = 'gray50', lty = 1) +

  geom_point(aes(size = status ), 
             shape = 16, position = position_jitter(seed = 0), show.legend = F) +
  scale_color_manual(name = "revenue") +
  geom_text(aes(label = revenue), size=4, vjust = 1.6, position = position_jitter(seed = 0)) + 

  theme_bw() +
  theme(
    axis.title = element_blank(),
    axis.ticks = element_blank(),
    plot.background = element_blank(), 
    axis.line = element_blank(), 
    panel.border = element_blank(), 
    panel.grid = element_blank(),

    axis.text = element_text(colour = "blue", face = "plain", size =11)
  ) +

  scale_x_continuous(limits=c(0.5,3.5), expand = c(0,0), breaks = 1:length(month_vector), labels = month_vector) +
  scale_y_continuous(limits=c(0.5,3.5), expand = c(0,0), breaks = 1:length(dept_vector), labels = dept_vector) +

  geom_hline(yintercept = as.numeric(sales_data$dept_name) + 0.5) +
  geom_vline(xintercept = as.numeric(sales_data$month) - 0.5, color = "grey")

输出图：

可以看到，geom_point绘制的点经常重叠。 为了解决重叠的问题，我正在考虑一个解决方案，但不确定如何使用R来完成。 需要指导。

步骤1）。在数据集（sales_data）中引入新列，该列在每个特定类别组合中具有点数。例如，对于类别Feb和Services，有6个输入项/点。因此，对于与此类Enter对应的所有行，新列的值应为6。

步骤2），我将计算每个类别组合中的输入项数的平方根，然后取该数字的上限。例如，类别案例Feb和Services有6个点，所以ceiling(squareroot(6)) =3。现在，我知道我必须通过分割x和y范围来绘制6点。类别为3 x 3网格。相应地，将在这些类别的图块内部的这9个网格点的前6个点上绘制点。

有人可以指导我，怎么做？ 我敢肯定，这很有可能，但不确定如何处理这种情况。