Make a Gantt chart using plotrix in R.

plotrix_gannt.R

library(plotrix)

# WHat follows is a copy and paste from
# https://www.rdocumentation.org/packages/plotrix/versions/3.7/topics/gantt.chart

Ymd.format<-"%Y/%m/%d"
gantt.info<-list(labels=
                   c("First task","Second task","Third task","Fourth task","Fifth task"),
                 starts=
                   as.POSIXct(strptime(
                     c("2004/01/01","2004/02/02","2004/03/03","2004/05/05","2004/09/09"),
                     format=Ymd.format)),
                 ends=
                   as.POSIXct(strptime(
                     c("2004/03/03","2004/05/05","2004/05/05","2004/08/08","2004/12/12"),
                     format=Ymd.format)),
                 priorities=c(1,2,3,4,5))
vgridpos<-as.POSIXct(strptime(c("2004/01/01","2004/02/01","2004/03/01",
                                "2004/04/01","2004/05/01","2004/06/01","2004/07/01","2004/08/01",
                                "2004/09/01","2004/10/01","2004/11/01","2004/12/01"),format=Ymd.format))
vgridlab<-
  c("Jan","Feb","Mar","Apr","May","Jun","Jul","Aug","Sep","Oct","Nov","Dec")
gantt.chart(gantt.info,main="Calendar date Gantt chart (2004)",
            priority.legend=TRUE,vgridpos=vgridpos,vgridlab=vgridlab,hgrid=TRUE)
# add a little extra space on the right side
gantt.chart(gantt.info,main="Calendar date Gantt chart (2004)",
            priority.legend=TRUE,vgridpos=vgridpos,vgridlab=vgridlab,hgrid=TRUE,
            xlim=as.POSIXct(strptime(c("2004/01/01","2004/12/20"),
                                     format=Ymd.format)))
# if both vgidpos and vgridlab are specified,
# starts and ends don't have to be dates
info2<-list(labels=c("Jim","Joe","Jim","John","John","Jake","Joe","Jed","Jake"),
            starts=c(8.1,8.7,13.0,9.1,11.6,9.0,13.6,9.3,14.2),
            ends=c(12.5,12.7,16.5,10.3,15.6,11.7,18.1,18.2,19.0))
gantt.chart(info2,vgridlab=8:19,vgridpos=8:19,
            main="All bars the same color",taskcolors="lightgray")
gantt.chart(info2,vgridlab=8:19,vgridpos=8:19,
            main="A color for each label",taskcolors=c(2,3,7,4,8))
gantt.chart(info2,vgridlab=8:19,vgridpos=8:19,
            main="A color for each interval - with borders",
            taskcolors=c(2,3,7,4,8,5,3,6,"purple"),border.col="black")