Hi All I have been trying to plot irregular XYZ data on world / country map, where X and Y are llongitude and latitude coordinates and Z is a variable. My problem is I get contour lines over water bodies. The method I follow is:> library(akima)> library(maps)> library(mapdata)> library(gpclib)> library(maptools)> ori <- read.table ("interp2.txt", header=T)> ori.li <- interp(ori$x, ori$y, ori$z)> ind<- readShapePoly("IND_adm0.shp")> plot(ori$y ~ ori$x, main = "ori data")> plot(ind, add=TRUE)>contour(ori.li, col= topo.colors (1), lwd=2, add=TRUE) Can someone please help me to draw the contour plot without the contour lines falling over water bodies like sea. I thank in advance for the time and help TrulyG. Arun Kumar Junior Research Fellow Dept of Immunology School of Biological Sciences Madurai Kamaraj University Madurai - 625 021 "An eye for an eye will only make the entire world blind."-Mohandas Karamchand Gandhi [[alternative HTML version deleted]]