CODEWITHSUNDEEP
rggplot2plotscatter-plot
V.MAT
V.MAT

Reputation: 55

How to plot three or more variables in a single scatterplot with automated equations?

I want to plot 2 variables from 3 different dataframes in one scatterplot and also plot the equations of each linear relationship automatically. I am using the following code. However I have two problems:

  1. I get the plots for the same values and not for the whole range (e.g. df1 =700 values, df2= 350 values, df3=450 values). What is the role of omitting the NA? Because I tried that both ways and I still get the same plot

  2. I can only add the equations as a text which means to run the lm function and then add the relathionship manually in the plot. I need to do that automatically.

The code that I am using is:

ggplot(df1, aes(x=noxppb, y=OX, colour = "red")) +
  geom_point(colour = "red", shape=2) +    # Use hollow circles
  geom_smooth(method=lm, se = FALSE) + 
  geom_point(data = df1, aes(x=noxppb, y=OX)) +
  geom_point(colour = "blue", shape=3) +
  geom_smooth(method = lm, se = F, colour = "blue", data = df2, aes(x=noxppb, y=OX)) +
  geom_point(colour = "green", shape=4) +
  geom_smooth(method = lm, se = F, colour = "green", data = df3, aes(x=noxppb, y=OX))

I get the following image: enter image description here

However I Need something similar to this: enter image description here

Upvotes: 0

Views: 1361

Answers (1)

baptiste
baptiste

Reputation: 77116

try this,

d <- plyr::mdply(data.frame(a=c(1,2,3), b=c(-1,0,1)), 
                 function(a,b) data.frame(x=seq(0,10), y=jitter(a*seq(0,10)+b)))


equationise = function(d, ...){
  m = lm(y ~ x, d)
  eq <- substitute(italic(y) == a + b %.% italic(x), 
                                        list(a = format(coef(m)[1], ...), 
                                             b = format(coef(m)[2], ...)))
  data.frame(x = Inf, y = d$y[nrow(d)], 
             label = as.character(as.expression(eq)),  
             stringsAsFactors = FALSE)
}


eqs <- plyr::ddply(d, "a", equationise, digits = 2)


ggplot(d, aes(x=x, y=y, colour = factor(a))) + 
  geom_point() +
  geom_smooth(method = "lm", se = FALSE) +
  geom_label(data=eqs, aes(label = label), parse=TRUE, hjust=1)

enter image description here

Upvotes: 3

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