ggplot2 put a bar plot (with continuous x-ax) on the same graph as a line graph

Question

users,

I have a continuous x-variable from 1-999 (I provide a sample of 20 observations of my data below to use).

I would like to plot some line graphs and a bar chart on the same plot such as this plot. The variable that I would like to plot on the bar chart is the variable "Irrigationtotal".

I have two problems: 1) the first problem is that for the bar chart, R only accepts discrete values on the x-asis. Therefore, it changes the order of my continuous values like: 1, 11, 101..., 2, 21, 22, ... 200, ... 3 33... And obviously, I want to have 1, 2, 3, 4, 5...

I realize I can use scale_x_discrete (limits = ...) for this problem, but then I think I will not be able to plot the line graph on the same plot as the bar chart.

2) The second problem is that I don't manage to get them nicely on top of each other while sharing the same x-axis.

Below you can find the code I have for the two graphs separately. Could somebody help with the problems described above? Thank you very much!

The data

out122<- structure(list(MEt_R = c(-0.0541818151603231, -0.0562844791428272, 
                     -0.0558715941992024, -0.0562399962945622, -0.0560460386125185, 
                     -0.0570608897132082, -0.0569943385875705, -0.0568252787782472, 
                     -0.0569942506473323, -0.0565197621205338, -0.056900534973487, 
                     -0.0571427349989937, -0.0569618449465491, -0.0566601716889117, 
                     -0.0563552308197707, -0.0568648464047371, -0.057047451157018, 
                     -0.0571837090302319, -0.0588902340655496, -0.0592472918164029
 ), MEt_Irr = c(-0.0930626749780042, -0.0924059309460578, -0.0924771937440385, 
           -0.0905386156125412, -0.0914934037180768, -0.0898948119109486, 
           -0.0898827200499507, -0.090372707751177, -0.0901901622784647, 
           -0.0914484064620663, -0.0925147845884521, -0.0927733849042059, 
           -0.0960873954367445, -0.0948131376144847, -0.0955133693827158, 
           -0.0933133384990093, -0.0927340360155418, -0.0925138612415783, 
           -0.0896139882242573, -0.0912014136494108), se_MEt_Rainfed = c(0.124867384884912, 
                                                                         0.124157398945455, 0.124169568385358, 0.124110270348855, 0.12391954965997, 
                                                                         0.123742628011372, 0.123766054757713, 0.123576175335345, 0.12353428904291, 
                                                                         0.123443556846824, 0.122869340273675, 0.122594726299249, 0.122332685310317, 
                                                                         0.12197210341919, 0.121115745201095, 0.120880251090657, 0.120851770150267, 
                                                                         0.120746714650168, 0.120922991632831, 0.120866928018865), se_MEt_Irrigation = c(0.0790595725119853, 
                                                                                                                                                         0.0819113174332981, 0.0818328749299557, 0.0834638025854297, 0.0818357384597404, 
                                                                                                                                                         0.0830466544695816, 0.0830677796154873, 0.0829941906461297, 0.083141965909444, 
                                                                                                                                                         0.082714324704666, 0.0809987066350066, 0.0810565659915952, 0.0792023249112186, 
                                                                                                                                                         0.0779277210970589, 0.0797106575341609, 0.0796897823245035, 0.0793238667046254, 
                                                                                                                                                         0.0794345101645159, 0.0805370559814554, 0.0816802765047257), 
 Irrigationtotal = c(3610, 3605, 3599, 3597, 3593, 3590, 3589, 
                3584, 3578, 3573, 3562, 3555, 3551, 3544, 3538, 3536, 3530, 
                3528, 3519, 3512)), .Names = c("MEt_R", "MEt_Irr", "se_MEt_Rainfed", 
                                               "se_MEt_Irrigation", "Irrigationtotal"), row.names = c(NA, 20L
                                               ), class = "data.frame")

Line graph

 out122$perc<-c(1:20)

 l64<-ggplot(out122,aes(perc))
 l65<-l64+geom_line(aes(y=MEt_R,colour="Rainfed"))+
   geom_line(aes(y=MEt_R+se_MEt_Rainfed,colour="Rainfed range"))+
   geom_line(aes(y=MEt_R-se_MEt_Rainfed,colour="Rainfed range"))+
   geom_line(aes(y=MEt_Irr,colour="Irrigation"))+
   geom_line(aes(y=MEt_Irr+se_MEt_Irrigation,colour="Irrigation range"))+
   geom_line(aes(y=MEt_Irr-se_MEt_Irrigation,colour="Irrigation range"))+

   scale_colour_manual(values=c("blue","light blue","green","light green"), name="")+
    scale_x_discrete(name="Threshold irrigation (in percentage)",breaks=c(0, 250, 500,750,1000),
               labels=c("0", "25", "50","75","100")) +
   scale_y_continuous(name="MEt",limits = c(-0.20, 0.5))+
   guides(fill=guide_legend(title=NULL))
 l66<-l65+ theme_bw()+ggtitle("subsidies 1 large") + 
   theme(plot.title = element_text(lineheight=.8, face="bold"))
 l66

Bar Graph (here I have the problem with the x-axis which is not ranked like 1, 2, 3...)

l1<- ggplot(data=out122, aes(x=rownames(out122), y=Irrigationtotal, fill=Irrigationtotal)) +
   geom_bar(stat="identity")+ theme_bw()
l1

Answer 1

I found an answer to my own question. I only still have a problem with the legend (which I will post in a new post).

To the problem of the order of the continuous x-axis, the answer is provided by:

out122$perc<- as.character(out221$perc)
out122$perc <- factor(out221$perc, levels=unique(foo.long$perc))

The answer to the problem on how to overlap the two graphs is found here.

Getting two legends under the combined graph can be done by following the suggestions here. The only think that I don't know yet is how to position the latter legend.