- Have a look at
scale_color_manual, the examples should be sufficient. The general structure of tweaking any scale in ggplot2 is to use the appropriate scale function:scale_{aes_name}_{scale_type}, whereaes_namecan becolor,x, or any other aeshetic, and wherescale_typecan becontinuous,discrete,manual, etc. - Googling for
ggplot2 legend positionled me to this link. Your answer is in there. - Have a look at
?theme, in particularpanel.background. The examples there include an example of exactly what you need.
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solved Several questions on ggplot2 [closed]