Ok, I've since found this: # called previously posted dataset "dat"
attach(dat) library(akima) data.interp <- interp(x,y,z) contour(data.interp) any idea how to calculate area within specified contour lines? Thanks chuck.01 wrote > > Hello, > I have some data that will be in the form: > > structure(list(station = structure(c(3L, 20L, 2L, 4L, 19L, 11L, > 1L, 5L, 10L, 12L, 17L, 18L, 6L, 9L, 13L, 16L, 7L, 8L, 15L, 14L > ), .Label = c("1", "10", "11", "12", "13", "14", "15", "16", > "17", "18", "19", "2", "3", "4", "5", "6", "7", "8", "9", "scope" > ), class = "factor"), distance = c(1.2, 0, 2, 0.8, 3, 1.7, 1, > 1.4, 2.8, 2.2, 4.5, 4.2, 2.8, 3.6, 3.4, 4.8, 3.8, 4.2, 4.8, 4.4 > ), degrees = c(-59, 0, 90, 89.9, 82.4, 69.4, 10.8, 45, 69, 26.6, > 63.4, 61.6, 45, 56.3, 28.1, 51.7, 38.7, 45, 38.3, 25.4), z = c(0L, > 0L, 0L, -1L, 0L, -1L, 0L, -1L, -1L, 0L, 0L, 0L, -1L, -1L, 0L, > 0L, -1L, -1L, 0L, 0L), x = c(-0.6, 0, 0, 0, 0.4, 0.6, 1, 1, 1, > 2, 2, 2, 2, 2, 3, 3, 3, 3, 3.8, 4), y = c(1, 0, 2, 0.8, 3, 1.6, > 0.19, 1, 2.6, 1, 4, 3.7, 2, 3, 1.6, 3.8, 2.4, 3, 3, 1.9)), .Names = > c("station", > "distance", "degrees", "z", "x", "y"), row.names = c(12L, 1L, > 11L, 13L, 10L, 20L, 2L, 14L, 19L, 3L, 8L, 9L, 15L, 18L, 4L, 7L, > 16L, 17L, 6L, 5L), class = "data.frame") > > > I would like to create a contour plot and eventually be able to calculate > the % area within each contour. > This only has 2 contour lines of height z=0, and z=-1; I would like to > have as many and these z values likely won't fall nicely into a contour > with others. Also, linear interpolation adding at least one point between > observed points would be great. > > This may give you an idea of the spatial arrangement of observations. > http://r.789695.n4.nabble.com/file/n4353603/Slide1.png > > Does anyone have any suggestions on how to begin doing this? > -- View this message in context: http://r.789695.n4.nabble.com/Contour-plot-with-messy-field-data-tp4353603p4353662.html Sent from the R help mailing list archive at Nabble.com. ______________________________________________ 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.