r - Manipulating x axis in panel plot when a factor is used -

the code i've used is:

mcgc <- ggplot(sam, aes(x = person,y = m, colour = x)) +               geom_point(size = 0.75) +               scale_colour_gradient2(high="red", mid="green", limits=c(0,1), guide = "colourbar") +               geom_hline(aes(yintercept = mad, linetype = "mad"), colour = "blue", size=0.75, show_guide = true) +               geom_hline(aes(yintercept = mmad, linetype = "mmad"), colour = "black", size=0.75, show_guide = true)  +               facet_wrap(~ plan, scales = "free", ncol = 4) +               scale_linetype_manual(name = "plan of health care", values = c("mad" = 1, "mmad" = 1),guide = "legend") 

for data:

plan  person x       m  mad  mmad 1  1 95 0.323000 0.400303 0.12 1  2 275 0.341818 0.400303 0.12 1  3  2 0.618000 0.400303 0.12 1  4 75 0.320000 0.400303 0.12 1  5 13 0.399000 0.400303 0.12 1  6 20 0.400000 0.400303 0.12 2  7 219 0.393000 0.353350 0.45 2  8 50 0.060000 0.353350 0.45 2  9 213 0.390000 0.353350 0.45 2  15 204 0.496100 0.353350 0.45 2  19 19 0.393000 0.353350 0.45 2  24 201 0.388000 0.353350 0.45 3  30 219 0.567 0.1254 0.89 3  14 50 0.679 0.1254 0.89 3  55 213 0.1234 0.1254 0.89 3  18 204 0.6135 0.1254 0.89 3  59 19 0.39356 0.1254 0.89 3  101 201 0.300 0.1254 0.89 

i'm trying manipulate x axis using:

scale_x_continuous(breaks = c(min(person), median(person), max(person)), labels = c(min(person), median(person), max(person)))  

however, given had change person factor order data properly, above code not work. errors, depending on how fiddle around code:

error: discrete value supplied continuous scale error in summary.factor(c(1l, 2l, 3l, 4l, 5l, 6l, 7l, 8l, 9l, 10l, 11l,  :    min not meaningful factors 

changing person numeric not work, accumulated person entire dataset on each plan figure panel, opposed scale specific each plan.

is there workaround this?

build plots separately , group them functions gridextra package.

require(ggplot2)  #set breaks , labels (min, median , max) in panel 1 sam1 = subset(sam,sam$plan==1) breaks1=c(min(sam1$person),median(sam1$person),max(sam1$person))  plan1 = ggplot(sam1, aes(x = person,y = m, colour=m)) +   geom_point(size = 2.5) +   scale_colour_gradient(limits=c(0,1), low="green", high="red", guide="none") +   geom_hline(aes(yintercept = mad, linetype = "solid"), colour = "blue", size=0.75, show_guide = true) +   geom_hline(aes(yintercept = mmad, linetype = "solid"), colour = "black", size=0.75, show_guide = true) +   scale_y_continuous(limits=c(0,1)) +   scale_x_continuous("",breaks=breaks1,labels=breaks1) +    ggtitle("1") +   theme_bw()  #set breaks , labels (min, median , max) in panel 2 sam2=subset(sam,sam$plan==2) breaks2=c(min(sam2$person),median(sam2$person),max(sam2$person))  plan2 = ggplot(sam2, aes(x = person,y = m, colour = m)) +   geom_point(size = 2.5) +   scale_colour_gradient(limits=c(0,1), low="green", high="red", guide="none") +   geom_hline(aes(yintercept = mad, linetype = "solid"), colour = "blue", size=0.75, show_guide = true) +   geom_hline(aes(yintercept = mmad, linetype = "solid"), colour = "black", size=0.75, show_guide = true)  +   scale_y_continuous("",limits=c(0,1)) +   scale_x_continuous("person",breaks=breaks2,labels=breaks2) +   ggtitle("2") +   theme_bw()  #set breaks , labels (min, median , max) in panel 3 sam3=subset(sam,sam$plan==3) breaks3=c(min(sam3$person),median(sam3$person),max(sam3$person))  plan3 = ggplot(sam3, aes(x = person,y = m, colour = m)) +   geom_point(size = 2.5) +   scale_colour_gradient(limits=c(0,1), low="green", high="red", guide="colourbar") +   geom_hline(aes(yintercept = mad, linetype = "mad"), colour = "blue", size=0.75, show_guide = true) +   geom_hline(aes(yintercept = mmad, linetype = "mmad"), colour = "black", size=0.75, show_guide = true)  +   scale_linetype_manual(name = "plan of health care", values = c("mad" = 1, "mmad" = 1),guide = "legend") +   scale_y_continuous("",limits=c(0,1)) +   scale_x_continuous("",breaks=breaks3,labels=breaks3) +   ggtitle("3") +   theme_bw()  #using function form user user971102, posted here: http://stackoverflow.com/questions/14920662/arrange-many-plots-using-gridextra g_legend<-function(a.gplot){   tmp <- ggplot_gtable(ggplot_build(a.gplot))   leg <- which(sapply(tmp$grobs, function(x) x$name) == "guide-box")   legend <- tmp$grobs[[leg]]   return(legend)}  mylegend = g_legend(plan3)  require(gridextra)  #adjusting panel widths code adapted user971102 , hrbrmstr's code, posted here: http://stackoverflow.com/questions/14920662/arrange-many-plots-using-gridextra grid.arrange(arrangegrob(plan1 + theme(legend.position="none"),                          plan2 + theme(legend.position="none"),                          plan3 + theme(legend.position="none"),                          ncol=3),mylegend,                          widths=unit(c(900,90),"pt"),nrow=1)