change both legend titles in a ggplot with two leg

问题:

I have two legends on my ggplot with two different legend titles (automatically created from ggplot()). Now, I want to change this legend titles. + labs(colour = "legend name") only change the second legend title. How can I change the first one, too?

Sample data:

dataset <- structure(list(date = structure(c(1264572000, 1266202800, 1277362800), 
class = c("POSIXt", "POSIXct"), tzone = ""), 
x1 = c(-0.00183760994446658, 0.00089738603087497, 0.000423513598318936), 
x2 = c("approach x","approach y","approach z"), 
x3 = c("Type1", "Type1", "Type2")) ,
.Names = c("date", "data","code","type"),
row.names = c("1", "2", "3"), class = "data.frame")

Here is my code to produce the plot:

p <- ggplot(dataset, aes(x=date, y=data)) +
geom_point(aes(shape = factor(type), color = code)) +
scale_shape_manual(value=c(23,15))
print(p)

The legend titles are on default: "factor(type)" and "code":

回答1:

Here is an example using the iris dataset:

data(iris)
ggplot(iris, aes(x=Sepal.Length, y=Sepal.Width)) +
    geom_point(aes(shape=Species, colour=Petal.Width)) + 
    scale_colour_gradient() +
    labs(shape="Species label", colour="Petal width label")

You specify the labels using labs(), with each scale separately specified, i.e. labs(shape="Species label", colour="Petal width label").

回答2:

If I understood your point correctly, you can simply use + labs(shape = "shape legend title", colour = "colour legend title")