向 R 中的曲面图添加永久等高线 plotly

Question

我正在使用 R 中的 plotly 包绘制曲面图和等高线图：

# Load package
library(plotly)

# Simulate the data for plotting
x <- y <- seq(from = 0, to = 100, by = 1)
z1 <- outer(X = x, Y = y, FUN = function(x, y) x^0.2 * y^0.3) # data for surface plot

# Draw surface plot (3D)
plotly::plot_ly(z = z1) %>%
  plotly::add_surface(
    contours = list(
      z = list(
        show = TRUE,
        usecolormap = TRUE,
        highlightcolor = "#ff0000",
        project = list(z = TRUE)
      ) 
    )    
  ) 

# Draw contour plot (2D)
plot_ly(z = z1) %>%
  add_contour()

两个图的渲染包含等高线，显示了 x 和 y 的组合，产生了一个恒定的 z 水平。在 3D 曲面图的情况下，将鼠标悬停在其上会动态绘制等高线，其中鼠标在 3 维 space.[=17= 的一侧投影等高线。 ]

我想做的是通过自己指定 z 的值（例如 z = 5）在两个地块上手动绘制一条或多条等高线。

Answer 1

感谢@IRTFM 的评论，我能够找到问题的答案。答案更具体到等高线图。用户需要将 contours 参数下的 start 和 end 属性设置为所需的 z 值。下面，我绘制了 z = 5:

的等高线

# Load package
library(plotly)

# Simulate the data for plotting
x <- y <- seq(from = 0, to = 100, by = 1)
z1 <- outer(X = x, Y = y, FUN = function(x, y) x^0.2 * y^0.3) # data for surface plot

plot_ly(
  z = z1,
  type = "contour",
  autocontour = FALSE,    
  colorscale = "RdBu",
  
  contours = list(
    start = 5,
    end = 5,
    showlabels = TRUE,
    showlines = TRUE,
    coloring = "lines"
  )
  
) %>%
 hide_guides()

如果想要绘制 2 条特定的等高线，他们需要一个额外的参数：ncontours = 2。不这样做可能会导致绘制超过 2 条等高线 - z 值介于 start 和 end 之间的线。

plot_ly(
  z = z1,
  type = "contour",
  autocontour = FALSE,
  
  ncontours = 2,
  
  colorscale = "RdBu",
  
  contours = list(
    start = 5,
    end = 7,
    showlabels = TRUE,
    showlines = TRUE,
    coloring = "lines"
  )
  
) %>%
 hide_guides()

最后，对于2条以上的特定轮廓线，我们需要使用add_contour()函数。让我们绘制 4 个特定的等高线图：

plot_ly(
  z = z1,
  type = "contour",
  autocontour = FALSE,
  
  ncontours = 2,
  
  colorscale = "RdBu",
  
  contours = list(
    start = 5,
    end = 7,
    showlabels = TRUE,
    showlines = TRUE,
    coloring = "lines"
  )
  
) %>% 
  
  add_contour(
    
    ncontours = 2,
    
    contours = list(
      start = 4,
      end = 6,
      showlabels = TRUE,
      showlines = TRUE,
      coloring = "lines"
    )
    
  ) %>%
  
  hide_guides()

向 R 中的曲面图添加永久等高线 plotly

Add a permanent contour line to a surface plot in R plotly

r

surface

contour

plotly

r-plotly