title: How to change line width in ggplot?
body: <p>Datalink:
  <a href="https://www.dropbox.com/s/yt4l10nel5bwxoq/GTAP_ConsIndex.csv">the data used</a></p>
  
  <p>My code:</p>
  
  <pre><code>ccfsisims &lt;- 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 &lt;- as.data.frame(ccfsisims)
  ccfsirsts[6:24] &lt;- sapply(ccfsirsts[6:24],as.numeric)
  ccfsirsts &lt;- droplevels(ccfsirsts)
  ccfsirsts &lt;- transform(ccfsirsts,sres=factor(sres,levels=unique(sres)))
  
  library(ggplot2)
  
  #------------------------------------------------------------------------------------------
  #### Plot of food security index for Morocco and Turkey by sector
  #------------------------------------------------------------------------------------------
  
  #_Code_Begin...
  
  datamortur &lt;- melt(ccfsirsts[ccfsirsts$region %in% c("TUR","MAR"), ]) # Selecting regions of interest
  datamortur1 &lt;- datamortur[datamortur$variable %in% c("pFSI2"), ] # Selecting the food security index of interest
  datamortur2 &lt;- datamortur1[datamortur1$sector %in% c("wht","gro","VegtFrut","osd","OthCrop","VegtOil","XPrFood"), ] # Selecting food sectors of interest
  datamortur3 &lt;- subset(datamortur2, tradlib !="BASEDATA") # Eliminating the "BASEDATA" scenario results  
  
  allfsi.f &lt;- datamortur3
  fsi.wht &lt;- allfsi.f[allfsi.f$sector %in% c("wht"), ]
  
  Figure29 &lt;- 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'))
  </code></pre>
  
  <p>My result:
  <img src="https://i.stack.imgur.com/oSMtm.png" alt="Result_Figure"> </p>
  
  <p>Newresult with aes(size=2):
  <img src="https://i.stack.imgur.com/ZZ0Tu.png" alt="NewResult-Figure"></p>
  
  <p>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.</p>
  
  <p>best,
  ismail </p>