如何在RStudio中将3D密度图与2D等高线图合并为一张图？

问题描述 #

我希望在RStudio中将密度图与等高线图合并为一张图，已编写代码生成两个独立的3D密度图和2D等高线图，代码如下：

library(MASS)
library(plotly)   
set.seed(123)

lambda1 <- 4
k1      <- 3
theta1  <- 5
k2      <- 1
theta2  <- 5    
num_simulations <- 1000


n <- rpois(num_simulations, lambda1)
n_truncated <- n[n > 0]
num_simulations <- length(n_truncated)

generate_gamma_sums <- function(counts, k, theta) {
sapply(counts, function(x) sum(rgamma(x, shape = k, scale = theta)))
}

ssx <- data.frame(
sx = generate_gamma_sums(n_truncated, k1, theta1),
sy = generate_gamma_sums(n_truncated, k2, theta2)
)

colnames(ssx) <- c("X", "Y")

density_data <- kde2d(ssx$X, ssx$Y, n = 50)

x_vals <- rep(density_data$x, each = length(density_data$y))
y_vals <- rep(density_data$y, length(density_data$x))
z_vals <- as.vector(density_data$z)

xlim <- range(density_data$x)
ylim <- range(density_data$y)

pdf_3d_plot <- plot_ly(x = ~x_vals, y = ~y_vals, z = ~z_vals, type = 'mesh3d', intensity = ~z_vals,
               showscale = TRUE, colorscale = list(c(0, 1), c("black", "white"))) %>%
  layout(
scene = list(
  xaxis = list(title = "X-axis", range = xlim, showgrid = TRUE, zeroline = FALSE, showline = TRUE),
  yaxis = list(title = "Y-axis", range = ylim, showgrid = TRUE, zeroline = FALSE, showline = TRUE),
zaxis = list(title = "Density", showgrid = TRUE, zeroline = FALSE),
 camera = list(eye = list(x = 1.5, y = 1.5, z = 1.2)) 
),
title = list(text = "3D PDF Surface", x = 0.5)
)

contour_2d_plot <- plot_ly(x = density_data$x, y = density_data$y, z = density_data$z,
                   type = "contour",
                   contours = list(coloring = "none", showlabels = TRUE),
                   line = list(color = 'black')) %>%
 layout(
xaxis = list(title = "X-axis", range = xlim, showgrid = TRUE, zeroline = FALSE, showline = TRUE),
yaxis = list(title = "Y-axis", range = ylim, showgrid = TRUE, zeroline = FALSE, showline = TRUE),
title = list(text = "2D Contour Plot", x = 0.5))

请问如何将生成的pdf_3d_plot与contour_2d_plot合并为一张图？

解决方案 #

可以使用Plotly的subplot()函数将两个子图组合到同一画布中，支持自定义布局（如上下排列、左右排列），同时可以统一调整整体标题和轴设置。以下是修改后的完整代码：

library(MASS)
library(plotly)   
set.seed(123)

lambda1 <- 4
k1      <- 3
theta1  <- 5
k2      <- 1
theta2  <- 5    
num_simulations <- 1000


n <- rpois(num_simulations, lambda1)
n_truncated <- n[n > 0]
num_simulations <- length(n_truncated)

generate_gamma_sums <- function(counts, k, theta) {
sapply(counts, function(x) sum(rgamma(x, shape = k, scale = theta)))
}

ssx <- data.frame(
sx = generate_gamma_sums(n_truncated, k1, theta1),
sy = generate_gamma_sums(n_truncated, k2, theta2)
)

colnames(ssx) <- c("X", "Y")

density_data <- kde2d(ssx$X, ssx$Y, n = 50)

x_vals <- rep(density_data$x, each = length(density_data$y))
y_vals <- rep(density_data$y, length(density_data$x))
z_vals <- as.vector(density_data$z)

xlim <- range(density_data$x)
ylim <- range(density_data$y)

pdf_3d_plot <- plot_ly(x = ~x_vals, y = ~y_vals, z = ~z_vals, type = 'mesh3d', intensity = ~z_vals,
               showscale = TRUE, colorscale = list(c(0, 1), c("black", "white"))) %>%
  layout(
scene = list(
  xaxis = list(title = "X-axis", range = xlim, showgrid = TRUE, zeroline = FALSE, showline = TRUE),
  yaxis = list(title = "Y-axis", range = ylim, showgrid = TRUE, zeroline = FALSE, showline = TRUE),
zaxis = list(title = "Density", showgrid = TRUE, zeroline = FALSE),
 camera = list(eye = list(x = 1.5, y = 1.5, z = 1.2)) 
),
title = list(text = "3D PDF Surface", x = 0.5)
)

contour_2d_plot <- plot_ly(x = density_data$x, y = density_data$y, z = density_data$z,
                   type = "contour",
                   contours = list(coloring = "none", showlabels = TRUE),
                   line = list(color = 'black')) %>%
 layout(
xaxis = list(title = "X-axis", range = xlim, showgrid = TRUE, zeroline = FALSE, showline = TRUE),
yaxis = list(title = "Y-axis", range = ylim, showgrid = TRUE, zeroline = FALSE, showline = TRUE),
title = list(text = "2D Contour Plot", x = 0.5))

# 合并两个子图，设置为上下排列（rows=2），也可改为cols=2实现左右排列
combined_plot <- subplot(pdf_3d_plot, contour_2d_plot, nrows = 2, shareX = TRUE, shareY = TRUE) %>%
  layout(title = list(text = "3D密度图与2D等高线图组合", x = 0.5),
         margin = list(l = 50, r = 50, t = 80, b = 50))

# 显示合并后的图
combined_plot

关键说明 #

• subplot()函数的nrows参数设置为2表示上下排列，若设为cols=2则为左右排列；
• shareX和shareY设为TRUE可让两个子图共享X/Y轴，保证坐标范围一致；
• 通过外层layout()可以统一设置整体标题和边距，让布局更美观。

内容的提问来源于stack exchange，提问作者miss alhejaili