在 R 中使用scatterplot3d，我试图从观察到回归平面绘制红线：
wh <- iris$Species != "setosa"
x <- iris$Sepal.Width[wh]
y <- iris$Sepal.Length[wh]
z <- iris$Petal.Width[wh]
df <- data.frame(x, y, z)
LM <- lm(y ~ x + z, df)
library(scatterplot3d)
G <- scatterplot3d(x, z, y, highlight.3d = FALSE, type = "p")
G$plane3d(LM, draw_polygon = TRUE, draw_lines = FALSE)
要获得下图的 3D 等效项：
在 2D 中，我可以使用segments：
pred <- predict(model)
segments(x, y, x, pred, col = 2)
但在 3D 中，我对坐标感到困惑。
我决定也包括我自己的实现，以防其他人想要使用它。
require("scatterplot3d")
# Data, linear regression with two explanatory variables
wh <- iris$Species != "setosa"
x <- iris$Sepal.Width[wh]
y <- iris$Sepal.Length[wh]
z <- iris$Petal.Width[wh]
df <- data.frame(x, y, z)
LM <- lm(y ~ x + z, df)
# scatterplot
s3d <- scatterplot3d(x, z, y, pch = 19, type = "p", color = "darkgrey",
main = "Regression Plane", grid = TRUE, box = FALSE,
mar = c(2.5, 2.5, 2, 1.5), angle = 55)
# regression plane
s3d$plane3d(LM, draw_polygon = TRUE, draw_lines = TRUE,
polygon_args = list(col = rgb(.1, .2, .7, .5)))
# overlay positive residuals
wh <- resid(LM) > 0
s3d$points3d(x[wh], z[wh], y[wh], pch = 19)
# scatterplot
s3d <- scatterplot3d(x, z, y, pch = 19, type = "p", color = "darkgrey",
main = "Regression Plane", grid = TRUE, box = FALSE,
mar = c(2.5, 2.5, 2, 1.5), angle = 55)
# compute locations of segments
orig <- s3d$xyz.convert(x, z, y)
plane <- s3d$xyz.convert(x, z, fitted(LM))
i.negpos <- 1 + (resid(LM) > 0) # which residuals are above the plane?
# draw residual distances to regression plane
segments(orig$x, orig$y, plane$x, plane$y, col = "red", lty = c(2, 1)[i.negpos],
lwd = 1.5)
# draw the regression plane
s3d$plane3d(LM, draw_polygon = TRUE, draw_lines = TRUE,
polygon_args = list(col = rgb(0.8, 0.8, 0.8, 0.8)))
# redraw positive residuals and segments above the plane
wh <- resid(LM) > 0
segments(orig$x[wh], orig$y[wh], plane$x[wh], plane$y[wh], col = "red", lty = 1, lwd = 1.5)
s3d$points3d(x[wh], z[wh], y[wh], pch = 19)
虽然我真的很欣赏该scatterplot3d函数的便利性，但最后我还是从 github 复制了整个函数，因为 baseplot中的几个参数要么被强制传递，要么没有正确传递给scatterplot3d（例如，轴旋转，las字符扩展cex，，cex.mainETC。）。我不确定这么长且凌乱的代码块在这里是否合适，所以我在上面包含了 MWE。
无论如何，这就是我最终包含在我的书中的内容：
（是的，那实际上只是 iris 数据集，不要告诉任何人。）
使用An Introduction to Statistical Learning中的广告数据集，您可以
advertising_fit1 <- lm(sales~TV+radio, data = advertising)
sp <- scatterplot3d::scatterplot3d(advertising$TV,
advertising$radio,
advertising$sales,
angle = 45)
sp$plane3d(advertising_fit1, lty.box = "solid")#,
# polygon_args = list(col = rgb(.1, .2, .7, .5)) # Fill color
orig <- sp$xyz.convert(advertising$TV,
advertising$radio,
advertising$sales)
plane <- sp$xyz.convert(advertising$TV,
advertising$radio, fitted(advertising_fit1))
i.negpos <- 1 + (resid(advertising_fit1) > 0)
segments(orig$x, orig$y, plane$x, plane$y,
col = c("blue", "red")[i.negpos],
lty = 1) # (2:1)[i.negpos]
sp <- FactoClass::addgrids3d(advertising$TV,
advertising$radio,
advertising$sales,
angle = 45,
grid = c("xy", "xz", "yz"))
另一个使用包的交互式版本rgl
rgl::plot3d(advertising$TV,
advertising$radio,
advertising$sales, type = "p",
xlab = "TV",
ylab = "radio",
zlab = "Sales", site = 5, lwd = 15)
rgl::planes3d(advertising_fit1$coefficients["TV"],
advertising_fit1$coefficients["radio"], -1,
advertising_fit1$coefficients["(Intercept)"], alpha = 0.3, front = "line")
rgl::segments3d(rep(advertising$TV, each = 2),
rep(advertising$radio, each = 2),
matrix(t(cbind(advertising$sales, predict(advertising_fit1))), nc = 1),
col = c("blue", "red")[i.negpos],
lty = 1) # (2:1)[i.negpos]
rgl::rgl.postscript("./pics/plot-advertising-rgl.pdf","pdf") # does not really work...
