Add regression plane in R using Plotly

问题

I recently tried to plot a regression pane in RStudio using the plotly library and read this post: Add Regression Plane to 3d Scatter Plot in Plotly

I followed the exact same procedure and ended up with a regression plane, which is obviously not correct:

EDIT: I followed the proposal in the first answer and my result looks like this:

Here is my code, I commented every step: sm is the data.frame I used

library(reshape2);
sm <- read.delim("Supermodel.dat", header = TRUE);
x1 <- sm$age
x2 <- sm$years
y <- sm$salary
df <- data.frame(x1, x2, y);


### Estimation of the regression plane
mod <- lm(y ~ x1+x2, data = df, na.action =     
        na.omit);

cf.mod <- coef(mod)

### Calculate z on a grid of x-y values
x1.seq <- seq(min(x1),max(x1),length.out=231)
x2.seq <- seq(min(x2),max(x2),length.out=231)
z.mtx <- t(outer(x1.seq, x2.seq, function(x1,x2) 
  cf.mod[1]+cf.mod[2]*x1+cf.mod[3]*x2))


#### Draw the plane with "plot_ly" and add points with "add_trace"
library(plotly) 

# Draw plane with plotly surface plot
plane <- plot_ly(x=~x1.seq, y=~x2.seq, z=~z.mtx, colors = 
c("#f5cb11", #b31d83"),type="surface") %>%
  add_trace(data=df, x=x1, y=x2, z=y, mode="markers", 
        type="scatter3d", 
        marker = list(color="black", opacity=0.7, symbol=105)) %>%
  layout(scene = list(aspectmode = "manual", aspectratio = list(x=1, 
    y=1, z=1), xaxis = list(title = "Age", range = c(12,24)), yaxis = 
    list(title = "Work experience (years)", range = c(0,10)), zaxis = 
list(title = "Salary p.a. (k)", range = c(0,90) )))

plane

I checked with the str-function, if the x1.seq and x2.seq have the same number of entries, and they both have 231 number values in them. The plane gets calculated and is shown, but it obviously still wrong.

PS: If you want to run the code, just download the file Supermodel.dat from Andy Fields website (https://studysites.uk.sagepub.com/dsur/study/articles.htm) under Regression.

Thanks in advance, rikojir

回答1:

Here is an illustrative example that shows how the observed points and the regression plane can be plotted together in a 3D plot generated using the plotlty package.
Hope it can help you.

### Data generating process
set.seed(1234)
n <- 50
x1 <- runif(n); x2 <- runif(n)
x3 <- rnorm(n)>0.5
y <- 2*x1-x2+rnorm(n, sd=0.25)
df <- data.frame(y, x1, x2, x3)

### Estimation of the regression plane
mod <- lm(y ~ x1+x2)
cf.mod <- coef(mod)

### Calculate z on a grid of x-y values
x1.seq <- seq(min(x1),max(x1),length.out=25)
x2.seq <- seq(min(x2),max(x2),length.out=25)
z <- t(outer(x1.seq, x2.seq, function(x,y) cf.mod[1]+cf.mod[2]*x+cf.mod[3]*y))

#### Draw the plane with "plot_ly" and add points with "add_trace"
cols <- c("#f5cb11", "#b31d83")
cols <- cols[x3+1] 
library(plotly)
p <- plot_ly(x=~x1.seq, y=~x2.seq, z=~z,
  colors = c("#f5cb11", "#b31d83"),type="surface") %>%
  add_trace(data=df, x=x1, y=x2, z=y, mode="markers", type="scatter3d",
  marker = list(color=cols, opacity=0.7, symbol=105)) %>%
  layout(scene = list(
    aspectmode = "manual", aspectratio = list(x=1, y=1, z=1),
    xaxis = list(title = "X1", range = c(0,1)),
    yaxis = list(title = "X2", range = c(0,1)),
    zaxis = list(title = "Y", range = pretty(z)[c(1,8)])))
print(p)

Here is the 3D plot generated by the above code:

来源：https://stackoverflow.com/questions/44322350/add-regression-plane-in-r-using-plotly

标签

regression

plotly

pane