Question

I wrote the following code to make time series plot by group.

nsplot<- xyplot(conc ~ time |Location, data=nspm1long, 
                ylim=range(nspm1long$conc),
                main="PM1 time series by Location", 
                ylab="PM1 concentration (mg/m3)",  
                xlab="Time", type="l",
                par.strip.text=list(cex=0.7), 
                par.settings=list(axis.text=list(cex=0.7)))
print(nsplot)

What I got is a block of thick line for the y-axis instead of the tickmarks like the x-axis. Would someone please help me fix the code. It would be even better if I could control the range of ylim like 0-0.5 and the number of tick marks.

I don’t know how to attach the image here and perhaps you could show me how too.

Answer 1

The output of your code looks fine for me. Here is what I get with some example data I made:

set.seed(12345)
data = expand.grid(time=1:100, Location=factor(1:3))
data$conc = with(data, 0.1*time + as.numeric(Location)) + rnorm(nrow(data))

See ?xyplot for the answers to all your plot formatting questions, specifically the scales, tick.number, ylim, tck parameters.