Hello, I use ggplot2 in order to represent the same data during 3 periods so I call facet_grid to get one subgraph by period. But when I do so, I get different results between the call on the whole data and the one on only one period (I expect to get one of the subgraphs to be identical to the graph obtained when using only one period). I added the code and my session info hereunder. Could you explain me what I do worng or if there is a bug? Thank you. Kind regards, Alain ------------------------------ library(ggplot2) # data tmp <- data.frame(x=rnorm(9000),y=rnorm(9000),color=factor(rep(1:3,each=3000)),period=factor(rep(1:3,3000)),ligne=factor(rep(1:2,4500))) # plot with the three periods ggplot(tmp,aes(x=x,y=y,col=color,linetype=ligne))+geom_smooth()+scale_colour_manual(values=c("black","blue","yellow"))+guides(linetype=FALSE,col=FALSE)+facet_grid(period~.) #plot with only the first period ggplot(tmp[tmp$period=="1",],aes(x=x,y=y,col=color,linetype=ligne))+geom_smooth()+scale_colour_manual(values=c("black","blue","yellow"))+guides(linetype=FALSE,col=FALSE)+facet_grid(period~.) ------------------------------ R version 3.3.1 (2016-06-21) Platform: x86_64-pc-linux-gnu (64-bit) Running under: Debian GNU/Linux 8 (jessie) locale: [1] LC_CTYPE=en_GB.UTF-8 LC_NUMERIC=C LC_TIME=en_GB.UTF-8 [4] LC_COLLATE=en_GB.UTF-8 LC_MONETARY=en_GB.UTF-8 LC_MESSAGES=en_GB.UTF-8 [7] LC_PAPER=en_GB.UTF-8 LC_NAME=C LC_ADDRESS=C [10] LC_TELEPHONE=C LC_MEASUREMENT=en_GB.UTF-8 LC_IDENTIFICATION=C attached base packages: [1] stats graphics grDevices utils datasets methods base other attached packages: [1] doBy_4.5-15 ggplot2_2.1.0 loaded via a namespace (and not attached): [1] Rcpp_0.12.5 lattice_0.20-33 digest_0.6.9 MASS_7.3-45 grid_3.3.1 [6] plyr_1.8.4 nlme_3.1-128 gtable_0.2.0 magrittr_1.5 scales_0.4.0 [11] stringi_1.1.1 reshape2_1.4.1 Matrix_1.2-6 labeling_0.3 tools_3.3.1 [16] stringr_1.0.0 munsell_0.4.3 colorspace_1.2-6 mgcv_1.8-12 -- Alain Guillet Statistician and Computer Scientist SMCS - IMMAQ - Universit? catholique de Louvain http://www.uclouvain.be/smcs Bureau c.316 Voie du Roman Pays, 20 (bte L1.04.01) B-1348 Louvain-la-Neuve Belgium Tel: +32 10 47 30 50 Acc?s: http://www.uclouvain.be/323631.html