向 3D 图添加等高线

Question

我正在使用 R 编程语言。我使用“plotly”库制作了以下 3 维图：

library(dplyr)
library(plotly)

  my_function <- function(x,y) {
    
    final_value = (1 - x)^2 + 100*((y - x^2)^2)
     
    }

input_1 <- seq(-1.5, 1.5,0.1)
input_2 <- seq(-1.5, 1.5,0.1)

z <- outer(input_1, input_2, my_function)

plot_ly(x = input_1, y = input_2, z = z) %>% add_surface()

我现在正尝试在上面的图中添加“等高线”，如下所示：https://plotly.com/r/3d-surface-plots/

我正在尝试调整“plotly 网站”中的代码来制作这些轮廓，但我不确定该怎么做：

图 1：

# This might have worked?
fig <- plot_ly(z = ~z) %>% add_surface(
  contours = list(
    z = list(
      show=TRUE,
      usecolormap=TRUE,
      highlightcolor="#ff0000",
      project=list(z=TRUE)
      )
    )
  )
fig <- fig %>% layout(
    scene = list(
      camera=list(
        eye = list(x=1.87, y=0.88, z=-0.64)
        )
      )
  )

图 2：

# I don't think this worked?
fig <- plot_ly(
  type = 'surface',
  contours = list(
    x = list(show = TRUE, start = 1.5, end = 2, size = 0.04, color = 'white'),
    z = list(show = TRUE, start = 0.5, end = 0.8, size = 0.05)),
  x = ~x,
  y = ~y,
  z = ~z)
fig <- fig %>% layout(
    scene = list(
      xaxis = list(nticks = 20),
      zaxis = list(nticks = 4),
      camera = list(eye = list(x = 0, y = -1, z = 0.5)),
      aspectratio = list(x = .9, y = .8, z = 0.2)))

fig

有人可以告诉我如何正确调整上述代码吗？

Answer 1

你快到了。
z 上的轮廓应根据 z:

的 min-max 值定义

plot_ly(x = input_1, y = input_2, z = z,
        contours = list(
          z = list(show = TRUE, start = round(min(z),-2),
                                end = round(max(z),-2), 
                                size = 100))) %>% 
        add_surface()

或由plotly自动设置：

plot_ly(x = input_1, y = input_2, z = z,
        colors = 'Oranges',
        contours = list(
          z = list(show = TRUE))) %>% 
  add_surface()

Answer 2

等高线在您的地块上，但由于 contours.z 列表中的参数，可能不是很明显。以下是调整轮廓线以满足您的需要的方法：

fig <- plot_ly(z = ~z) %>% add_surface(
  contours = list(
    z = list(
      show = TRUE,
      # project=list(z=TRUE)       # (don't) project contour lines to underlying plane
      # usecolormap = TRUE,        # (don't) use surface color scale for contours
      color = "white",             # set contour color
      width = 1,                   # set contour thickness
      highlightcolor = "#ff0000",  # highlight contour on hover
      start = 0,                   # include contours from z = 0...
      end = 1400,                  # to z = 1400...
      size = 100                   # every 100 units

    )
  )
)

您可以通过将列表传递给 x 或 y 来沿其他维度绘制线条。（根据来自 OP 的 follow-up 问题）您可以使用 colorscale 更改表面色标，指定 named colorscale options 之一或构建您自己的。示例：

fig <- plot_ly(z = ~z) %>% add_surface(
  colorscale = "Picnic",
  contours = list(
    x = list(show=TRUE, color="#a090b0", width=2, start=0, end=30, size=7.5),
    y = list(show=TRUE, color="#a090b0", width=2, start=0, end=30, size=7.5),
    z = list(show=TRUE, color="#a090b0", width=2, start=0, end=1400, size=300)
  )
)

向 3D 图添加等高线

Adding Contour Lines to 3D Plots

3d

r

data-visualization

plotly