直方图中 y 轴的奇怪行为

Question

我想使用 ggivs 将一组不同变量的直方图放在同一个缩放的 y 轴上。但是，一旦我的坐标轴明显大于变量的最高计数，它们就会开始变得非常奇怪，甚至开始在负方向上绘制条形图。这是我的数据http://rpubs.com/elinw/116698

这是一个可重现的例子

# no values specified
iris %>% ggvis(~Sepal.Width) %>% layer_histograms(width = 1)  %>%
   add_axis("y", title = "Count", title_offset="50") 
   add_axis("x", title = "Width", title_offset="50") 

#0 to 150
 iris %>% ggvis(~Sepal.Width) %>% layer_histograms(width = 1)  %>%
   add_axis("y", title = "Count", title_offset="50",  values = seq(0,150, by = 10))  %>%
   add_axis("x", title = "Width", title_offset="50") 

  #0 to 175
 iris %>% ggvis(~Sepal.Width) %>% layer_histograms(width = 1)  %>%
   add_axis("y", title = "Count", title_offset="50",  values = seq(0,200, by = 10))  %>%
   add_axis("x", title = "Width", title_offset="50") 

 #0 to 250
 iris %>% ggvis(~Sepal.Width) %>% layer_histograms(width = 1)  %>%
   add_axis("y", title = "Count", title_offset="50",  values = seq(0,250, by = 10))  %>%
   add_axis("x", title = "Width", title_offset="50") 

#0 to 500
 iris %>% ggvis(~Sepal.Width) %>% layer_histograms(width = 1)  %>%
   add_axis("y", title = "Count", title_offset="50",  values = seq(0,500, by = 10)) 
   add_axis("x", title = "Width", title_offset="50") 

我已阅读文档，但对此一无所知。我可以更改属性中的某些内容以使其正常工作吗？或者对此有已知的规则吗？还是bug？

Answer 1

add_axis 中的参数 values 仅设置刻度在轴上的位置，但不会更改轴的最小和最大限制 (ylim/xlim)。根据ggvis doc，您需要在scale_numeric() 中设置参数domain。试试这个：

iris %>% ggvis(~Sepal.Width) %>% layer_histograms(width = 1)  %>%
  add_axis("y", title = "Count", title_offset="50",  values = seq(0,150, by = 10))  %>%
  ## Set axis limits:
  scale_numeric("y", domain = c(0, 150), nice = FALSE) %>% 
  add_axis("x", title = "Width", title_offset="50")

你可以在这里看到所有的情节：http://rpubs.com/scoa/116718