Using factor levels with geom_rect


I have factor levels like "node002" "node004" "node006" "node016" "node017" "node018" which are being plotted against dates. I am trying to underlay a given factor level for a period using geom_rect. For the dates, I can do something like ymin=as.Date("8-Apr-2014", format="%d-%b-%Y").

Is it possible to I stipulate, say ymin in terms of the factor levels? If so, how would it be done?

Here is some more information to try to clarify the issue:

The data look like this:

17-Mar-2014 node004 node016 node018 node020 node025 node034 node041 15-Sep-2014 node002 node016 node061 node098 8-Sep-2014 node002 node016 node020 node061 1-Sep-2014 node002 node016 node020 node061 25-Aug-2014 node002 node020 node061 11-Aug-2014 node006 node020 4-Aug-2014 node020 28-Jul-2014 node020 21-Jul-2014 node020 14-Jul-2014 node016 node020 node061 7-Jul-2014 node016 node020 node061 30-Jun-2014 node016 node020 node061 23-Jun-2014 node016 node020 node061 7-Apr-2014 node004 node018 node025 node034 node041 node057 10-Mar-2014 node004 node016 node018 node020 node025 node034 node041 3-Mar-2014 node004 node016 node018 node020 node025 node034 node041 19-Aug-2013 node016 node018 node025 node057 node065 12-Aug-2013 node025 node057 node080 5-Aug-2013 node020 node025 node080 29-Jul-2013 node020 node025 node080 22-Jul-2013 node025 node080 15-Jul-2013 node025 node080 8-Jul-2013 node025 1-Jul-2013 node025 24-Jun-2013 node025 17-Jun-2013 node025 27-May-2013 node057 13-May-2013 node018 node025 node057 node080 6-May-2013 node017 node018 node025 node057 29-Apr-2013 node018 22-Apr-2013 node018 node020 node025 node050 node080 15-Apr-2013 node018 node020 node025 node080 8-Apr-2013 node018 node020 node025 node080 1-Apr-2013 node018 node020 node025 node080 25-Mar-2013 node017 node080 18-Mar-2013 node047 11-Mar-2013 node025 25-Feb-2013 node034 18-Feb-2013 node034 11-Feb-2013 node025 node034 node061 4-Feb-2013 node025 node034 node061 28-Jan-2013 node025 node034 node061 21-Jan-2013 node025 node034 node050 node061 14-Jan-2013 node025 node034 node061 7-Jan-2013 node025 node061*emphasized text* 16-Jun-2014 node016 node020 node061 9-Jun-2014 node016 node020 node061 2-Jun-2014 node016 node020 node061 26-May-2014 node016 node020 node061 19-May-2014 node020 node061 12-May-2014 node016 node020 node061 5-May-2014 node020 28-Apr-2014 node004 node018 node025 node034 node041 node057 21-Apr-2014 node004 node016 node018 node025 node034 node041 node057 14-Apr-2014 node004 node016 node018 node025 node034 node041 node057 31-Mar-2014 node004 node018 node025 node034 node041 node057 24-Mar-2014 node004 node018 node020 node034 node041 node057 17-Feb-2014 node004 node016 node018 node034 10-Feb-2014 node004 node018 node020 3-Feb-2014 node004 node018 node025 27-Jan-2014 node004 node018 node020 node025 20-Jan-2014 node004 node018 node020 node025 13-Jan-2014 node004 node018 node020 node025 node041 6-Jan-2014 node016 node020 node025 node041 node047 node082 30-Dec-2013 node016 node020 node025 node041 23-Dec-2013 node016 node020 node025 node041 node057 16-Dec-2013 node020 node025 node041 node087 9-Dec-2013 node016 node018 node020 node025 node065 2-Dec-2013 node018 node020 node025 25-Nov-2013 node020 node025 18-Nov-2013 node020 node025 11-Nov-2013 node020 4-Nov-2013 node020 28-Oct-2013 node016 node020 node025 21-Oct-2013 node025 14-Oct-2013 node017 node020 node025 7-Oct-2013 node020 node025 30-Sep-2013 node016 node020 node025 23-Sep-2013 node020 node025 node057 16-Sep-2013 node025 node057 9-Sep-2013 node025 2-Sep-2013 node016 node025 26-Aug-2013 node016 node018 node025 node057 node065 18-Aug-2014 node002 node006 node020

The code I have tried looks like this

require(ggplot2) require(reshape2) require(scales) df <- read.table("~/tmp/ipmi_data.txt",fill=T) flatdata <- melt(df,id.vars="V1") flatdata <- flatdata[!flatdata$value=="",] flatdata <- flatdata[order(flatdata$value),] flatdata$value <- factor(flatdata$value,levels=sort(levels(flatdata$value))) ggplot(flatdata[flatdata$value != "",]) + geom_point(aes(x=value,y=as.Date(V1,format="%d-%b-%Y")),size=3,alpha=0.9) + scale_x_discrete(name="Node") + ylab("Date") + geom_rect(aes(ymin=as.Date("8-Apr-2014", format="%d-%b-%Y"), ymax=as.Date("30-Apr-2014", format="%d-%b-%Y"), xmin="node002",xmax="node098"), fill="red", alpha=0.25) + coord_flip()

The resulting graph has a rectangle across all the factor levels:

<img alt="Resulting Graph" class="b-lazy" data-src="https://i.stack.imgur.com/ID1G4.png" data-original="https://i.stack.imgur.com/ID1G4.png" src="https://etrip.eimg.top/images/2019/05/07/timg.gif" />

However, I would like to have individual rectangle for specific levels, such a only for "node004" and "node057" in a given date interval.

So the question is whether is is possible to use the index of a level as a coordinate to define the vertical extent of the rectangle and, if so, how?


I got some help after asking the same question on the comp.lang.r.general mailing list (<a href="http://permalink.gmane.org/gmane.comp.lang.r.general/313656" rel="nofollow">http://permalink.gmane.org/gmane.comp.lang.r.general/313656</a>). I ended up adding the following:

nodelist <- sort(levels(flatdata$value))

and then using

geom_rect(aes(ymin=as.Date("8-Apr-2014", format="%d-%b-%Y"), ymax=as.Date("30-Apr-2014", format="%d-%b-%Y"), xmin=which(nodelist=="node004")-0.5, xmax=which(nodelist=="node004")+0.5, fill="red", alpha=0.25))