Deepayan: Very nice, thanks for introducing me to a new resource. I will include the entire, functioning example in the event others may find it useful.
--Seth ###### Sample code for overlaying data points on a contour graph, using xyplot and contourplot ################## library(lattice) model <- function(a,b,c,X1,X2) # provide model function for contour plot {(exp(a + b*X1 + c*X2)) / (1 + exp(a + b*X1 + c*X2))} g <- expand.grid(X1 = seq(0.38, 0.8,0.01), X2 = seq(0.03,0.99,0.03)) # create gridded data for contour plot a <- -37.61 # Assign value to 'a' parameter b <- 34.88 # Assign value to 'b' parameter c <- 28.44 # Assign value to 'c' parameter g$z<- model(a, b, c, g$X1,g$X2) # Create variable z using gridded data, model, and variables # Data to superimpose as xyplot on the contourplot.... ph <-c(0.42,0.47,0.59,0.40) # Create a vector of values under variable 'ph' phh <-c(0.76,0.81,0.82,0.71) # Create vector of values for variable 'phh' d <- data.frame(ph,phh) # Group variables ph & phh in data frame 'd' contourplot(z ~ X1 * X2, data=g, contour=TRUE, xlim=c(0.38,0.8), ylim=c(0.401,0.999), zlim=c(0,1), # Set Axis Ranges xlab="p(H)", ylab="p(H|H)", # Set axis labels region = TRUE, cuts=10, panel = function(x,y,subscripts,...){ panel.contourplot(x,y,subscripts,...) panel.xyplot(d$ph,d$phh)} ) #### End ############################## ______________________________________________ R-help@r-project.org mailing list 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.