I would like to split the legend that is generated by ggplot based on the variables that are taken from the data frame. I'm starting from melted data.
Using the Iris data set, I'd like to get this:
What I'm looking for is to obtain a legend box that includes only the Sepal variables and another legend box with Petal variables. Originally I'm dealing with similar data from different sources and would like to make clear to which source belong certain variables.
