直方圖中y軸的奇怪行爲

Question

我想使用ggivs將一組不同變量的直方圖全部放在同一個縮放的y軸上。然而，一旦我的座標軸變得比變量的最大值大得多，他們就開始變得非常奇怪，甚至開始在負方向上繪製豎線。這是我的數據http://rpubs.com/elinw/116698

這裏是一個可再現例如

# 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") 

我讀過的文件，但我不認爲這事。我可以改變這些功能來改變這些功能嗎？還是有一個關於這個的已知規則？或者它是一個錯誤？

Answer 1

參數values在add_axis中只設置了座標軸在軸上的位置，但它不會更改軸的最小和最大限制（ylim/xlim）。根據ggvis doc，您需要在scale_numeric()中設置參數domain。試試這個：

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") 

這裏你可以看到所有的情節：http://rpubs.com/scoa/116718