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Creating 3D Plots in R Programming – persp() Function

  • Last Updated : 08 Jun, 2020
Geek Week

3D plot in R Language is used to add title, change viewing direction, and add color and shade to the plot. The persp() function which is used to create 3D surfaces in perspective view. This function will draw perspective plots of a surface over the x–y plane. persp() is defines as a generic function. Moreover, it can be used to superimpose additional graphical elements on the 3D plot, by lines() or points(), using the function trans3d().

Syntax: persp(x, y, z)

Parameter: This function accepts different parameters i.e. x, y and z where x and y are vectors defining the location along x- and y-axis. z-axis will be the height of the surface in the matrix z.

Return Value: persp() returns the viewing transformation matrix for projecting 3D coordinates (x, y, z) into the 2D plane using homogeneous 4D coordinates (x, y, z, t).

Example 1: Simple Right Circular Cone






# To illustrate simple right circular cone
cone <- function(x, y){
sqrt(x ^ 2 + y ^ 2)
}
  
# prepare variables.
x <- y <- seq(-1, 1, length = 30)
z <- outer(x, y, cone)
  
# plot the 3D surface
persp(x, y, z)

Output:

  • Here in above code, function seq() to generate vector of equally spaced numbers.
  • the outer() function to apply the function cone at every combination of x and y.

Example 2: Adding Titles and Labeling Axes to Plot




# Adding Titles and Labeling Axes to Plot
cone <- function(x, y){
sqrt(x ^ 2 + y ^ 2)
}
  
# prepare variables.
x <- y <- seq(-1, 1, length = 30)
z <- outer(x, y, cone)
  
# plot the 3D surface
# Adding Titles and Labeling Axes to Plot
persp(x, y, z,
main="Perspective Plot of a Cone",
zlab = "Height",
theta = 30, phi = 15,
col = "orange", shade = 0.4)

Output:

  • Here in above code, xlab, ylab and zlab can be used to label the three axes.
  • theta and phi are viewing direction.

Example 3: Visualizing a simple DEM(Digital elevation model)




# Visualizing a simple DEM model
  
z <- 2 * volcano        # Exaggerate the relief
x <- 10 * (1:nrow(z))   # 10 meter spacing (S to N)
y <- 10 * (1:ncol(z))   # 10 meter spacing (E to W)
  
  
# Don't draw the grid lines :  border = NA
par(bg = "gray")
persp(x, y, z, theta = 135, phi = 30, col = "brown", scale = FALSE,
      ltheta = -120, shade = 0.75, border = NA, box = FALSE)

Output:




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