Sorry i forgot to give the Rscript to execute with the datas in the archive attached : limite_x<-structure(as.numeric(read.table("limite_x")), class=c("POSIXt","POSIXct")) limite_y<-as.numeric(read.table("limite_y")) test<-as.numeric(read.table("y_values")) abscisse_test<-structure(as.numeric(read.table("x_values")), class=c("POSIXt","POSIXct")) plot((test/10)~abscisse_test,type="s",col="lightgreen",xlab="",ylab="",ylim=limite_y,xlim=limite_x) length_test<-length(test) #if i cut the var "test" to be closer to xlim values, i know that xlim is at the end of "test" : test_short<-test[(length_test-10):length_test] abscisse_test_short<-abscisse_test[(length_test-10):length_test] plot((test_short/10)~abscisse_test_short,type="s",col="lightgreen",xlab="",ylab="",ylim=limite_y,xlim=limite_x) dev.off() COMTE Guillaume Ing?nieur Projet Alliance Technologies Projet Philharmonie 24 rue Martre 92110 Clichy Tel : 01 40 87 48 06 Fax : 01 40 87 48 14