How to change line width in ggplot?

Question

Datalink: the data used

My code:

ccfsisims <- read.csv(file = "F:/Purdue University/RA_Position/PhD_ResearchandDissert/PhD_Draft/GTAP-CGE/GTAP_NewAggDatabase/NewFiles/GTAP_ConsIndex.csv", header=TRUE, sep=",", na.string="NA", dec=".", strip.white=TRUE)
ccfsirsts <- as.data.frame(ccfsisims)
ccfsirsts[6:24] <- sapply(ccfsirsts[6:24],as.numeric)
ccfsirsts <- droplevels(ccfsirsts)
ccfsirsts <- transform(ccfsirsts,sres=factor(sres,levels=unique(sres)))

library(ggplot2)

#------------------------------------------------------------------------------------------
#### Plot of food security index for Morocco and Turkey by sector
#------------------------------------------------------------------------------------------

#_Code_Begin...

datamortur <- melt(ccfsirsts[ccfsirsts$region %in% c("TUR","MAR"), ]) # Selecting regions of interest
datamortur1 <- datamortur[datamortur$variable %in% c("pFSI2"), ] # Selecting the food security index of interest
datamortur2 <- datamortur1[datamortur1$sector %in% c("wht","gro","VegtFrut","osd","OthCrop","VegtOil","XPrFood"), ] # Selecting food sectors of interest
datamortur3 <- subset(datamortur2, tradlib !="BASEDATA") # Eliminating the "BASEDATA" scenario results  

allfsi.f <- datamortur3
fsi.wht <- allfsi.f[allfsi.f$sector %in% c("wht"), ]

Figure29 <- ggplot(data=fsi.wht, aes(x=factor(sres),y=value,colour=factor(tradlib)))
Figure29 + geom_line(aes(group=factor(tradlib),size=2)) + facet_grid(regionsFull~., scales="free_y", labeller=reg_labeller) + scale_colour_brewer(type = "div") +
theme(axis.text.x = element_text(colour = 'black', angle = 90, size = 13, hjust = 0.5, vjust = 0.5),axis.title.x=element_blank()) + 
ylab("FSI (%Change)") + theme(axis.text.y = element_text(colour = 'black', size = 12), axis.title.y = element_text(size = 12, hjust = 0.5, vjust = 0.2)) + 
theme(strip.text.y = element_text(size = 11, hjust = 0.5, vjust = 0.5, face = 'bold'))

My result:

Newresult with aes(size=2):

My question: Is there a way to control for line width more precisely to avoid the result in the second plot? I particularly find it document-unfriendly, and more so for publishing purposes to include the plot with the newly defined line width.

best, ismail

Intemperate

To change line width, just add argument size=2 to geom_line(). – Overtask

Just did some experimentation and it looks like size doesn't have to assume integral values as you're using with 1 and 2. I just entered 1.5 and got something in-between. I'm not sure if a fixed value like that would work for you under all circumstances but it does appear tunable at least. – Osyth

Answer 1

Whilst @Didzis has the correct answer, I will expand on a few points

Aesthetics can be set or mapped within a ggplot call.

• An aesthetic defined within aes(...) is mapped from the data, and a legend created.

• An aesthetic may also be set to a single value, by defining it outside aes().

As far as I can tell, what you want is to set size to a single value, not map within the call to aes()

When you call aes(size = 2) it creates a variable called `2` and uses that to create the size, mapping it from a constant value as it is within a call to aes (thus it appears in your legend).

Using size = 1 (and without reg_labeller which is perhaps defined somewhere in your script)

Figure29 +
    geom_line(aes(group=factor(tradlib)),size=1) +
    facet_grid(regionsFull~., scales="free_y") +
    scale_colour_brewer(type = "div") +
    theme(axis.text.x = element_text(
          colour = 'black', angle = 90, size = 13,
          hjust = 0.5, vjust = 0.5),axis.title.x=element_blank()) +
    ylab("FSI (%Change)") +
    theme(axis.text.y = element_text(colour = 'black', size = 12), 
          axis.title.y = element_text(size = 12, 
          hjust = 0.5, vjust = 0.2)) + 
    theme(strip.text.y = element_text(size = 11, hjust = 0.5,
          vjust =    0.5, face = 'bold'))

and with size = 2

 Figure29 + 
     geom_line(aes(group=factor(tradlib)),size=2) +
     facet_grid(regionsFull~., scales="free_y") + 
     scale_colour_brewer(type = "div") +
     theme(axis.text.x = element_text(colour = 'black', angle = 90,
          size = 13, hjust = 0.5, vjust = 
          0.5),axis.title.x=element_blank()) + 
     ylab("FSI (%Change)") +
     theme(axis.text.y = element_text(colour = 'black', size = 12),
          axis.title.y = element_text(size = 12,
          hjust = 0.5, vjust = 0.2)) + 
      theme(strip.text.y = element_text(size = 11, hjust = 0.5,
          vjust = 0.5, face = 'bold'))

You can now define the size to work appropriately with the final image size and device type.

Martyrology

Great answer. Update with ggplot3.4.0, the new argument is linewidth instead of size. – Micco

Answer 2

Line width in ggplot2 can be changed with argument size= in geom_line().

# sample data
df <- data.frame(x = rnorm(100), y = rnorm(100))
ggplot(df, aes(x = x, y = y)) + 
  geom_line(size = 2)

Overtask

I have already tried your option, but the problem is that the line become too thick to be considered document-friendly. When using the aes(size), I get the second graph that I added. I want to be able to control for the width in a more systematic way so as to choose the best fit. – Intemperate

@smailov83, don't put size within the call to aes. See my answer (or the ggplot2 book for an explanation. – Martyrology

Default value seems to be less than size=1, maybe 0.5, so using size=1 yields quite good results in my opinion. One can also use decimal numbers to fine tune the width (say size=1.2). – Statecraft

Note that from ggplot2 3.4.0, size is superseded for lines and is now replaced by the more explicit linewidth. – Immitigable

Answer 3

Line width in ggplot2 can be changed with argument lwd= in geom_line().

geom_line(aes(x=..., y=..., color=...), lwd=1.5)

Partin

worked for me today in geom_hline where "size=" is not recognized – Delk

I believe the argument is called linewidth in current versions of ggplot. Also lineend="square" extends the line while "butt" only increases width. – Doss

Answer 4

It also looks like if you just put the size argument in the geom_line() portion but without the aes() it will scale appropriately. At least it works this way with geom_density and I had the same problem.

Tuck

Answer 5

If you want to modify the line width flexibly you can use "scale_size_manual," this is the same procedure for picking the color, fill, alpha, etc.

library(ggplot2)
library(tidyr)

x = seq(0,10,0.05)

df <- data.frame(A = 2 * x + 10,
                 B = x**2 - x*6,
                 C = 30 - x**1.5,
                 X = x)


df = gather(df,A,B,C,key="Model",value="Y")


ggplot( df, aes (x=X, y=Y, size=Model, colour=Model ))+
  geom_line()+
  scale_size_manual( values = c(4,2,1) ) +
  scale_color_manual( values = c("orange","red","navy") ) 

Spancake

Answer 6

Since ggplot2 3.4.0. use linewidth.

For example:

geom_line(aes(group=factor(tradlib)), linewidth=0.2)

Dowzall

Answer 7

Just add the size command outside the aes() function, with any fractional value desired, e.g. size = 1.5

geom_line(data,aes(x=x,y=y), size=1.5)

Consubstantiate