Instead of trying to mix lattice and base functions, you might try using the formula:
maxtemp+mintemp ~ sampdate And then: col= c(“red”, “blue”) Sent from my iPhone, so make sure those quotes are ordinary double quotes. — David > On Sep 27, 2019, at 6:27 AM, Rich Shepard <rshep...@appl-ecosys.com> wrote: > > I want to plot maximum and minimum water temperatures on the same axes and > thought I had the correct syntax: > > watertemp <- read.table("../../data/hydro/water-temp.dat", header = TRUE, sep > =",") > watertemp$sampdate <- as.Date(as.character(watertemp$sampdate)) > watertempsum <- summary(watertemp) > print(watertempsum) > maxwatemp <- xyplot(maxtemp ~ sampdate, data=watertemp, col="red", type="h", > main="USGS Foss Gauge Water Temperatures, 1974-1981", ylab="Temperature (C)", > xlab="Date", scales=list(tck=c(1,0))) > minwatemp <- xyplot(mintemp ~ sampdate, data=watertemp, col="blue", type="h") > plot(maxwatemp) > par(new=TRUE) > plot(minwatemp) > > However, R plots only minwatemp and displays this: > Warning message: > In par(new = TRUE) : calling par(new=TRUE) with no plot > > Despite my searching for the reason I don't see what syntax error I made. > The two questions I ask of you: > > 1. Where have I gone wrong in this script? > > 2. With 2,492 daily observations in the source file (including 242 NAs for > maxtemp and 243 NAs for mintemp), what would be a more appropriate plot to > show both sets of data? > > Thanks in advance, > > Rich > > ______________________________________________ > R-help@r-project.org mailing list -- To UNSUBSCRIBE and more, see > https://stat.ethz.ch/mailman/listinfo/r-help > PLEASE do read the posting guide http://www.R-project.org/posting-guide.html > and provide commented, minimal, self-contained, reproducible code. ______________________________________________ R-help@r-project.org mailing list -- To UNSUBSCRIBE and more, see https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code.