Hi Eliza I think this comes close to what you want (escaping manual work).
library("maps") library("sp") ## has a point.in.polygon function ireland <- map("world", "ireland") map.axes() xr <- range(ireland$x, na.rm = TRUE) yr <- range(ireland$y, na.rm = TRUE) xseq <- seq(xr[1], xr[2], by = 0.1) yseq <- seq(yr[1], yr[2], by = 0.1) xy <- expand.grid(longitude = xseq, latitude = yseq) ## grid lines abline(v = xseq, col = "grey80", lty = 3) abline(h = yseq, col = "grey80", lty = 3) ## grid points ireland <- map("world", "ireland") map.axes() points(xy, pch = ".") ## get ireland map as polygon, only for main island ## map.poly not exported so use maps:::map.poly ## use exact to leave out Achill Island and only get main island ie.polygon <- maps:::map.poly("world", "Ireland", exact = TRUE, as.polygon = TRUE) ## x[1] and y[1] added to close polygon index <- point.in.polygon(xy$longitude, xy$latitude, c(ie.polygon$x, ie.polygon$x[1]), c(ie.polygon$y, ie.polygon$y[1])) table(index) ireland <- map("world", "Ireland", exact = TRUE) # leaving out Achill points(xy, pch = ".", cex = 1) map.axes() ## index: 0: outside, 1: border, 3: inside points(xy[index > 0,], pch = 1, col = "red", cex = 0.9) ## If you need Achill Island as well then do the same for this region also print(regionNames <- map("world", "ireland", plot = FALSE, namesonly = TRUE)) ireland <- map("world", "Ireland:Achill Island", exact = TRUE, xlim = xr, ylim = yr) Yours sincerely / Med venlig hilsen Frede Aakmann Tøgersen Specialist, M.Sc., Ph.D. Plant Performance & Modeling Technology & Service Solutions T +45 9730 5135 M +45 2547 6050 fr...@vestas.com http://www.vestas.com Company reg. name: Vestas Wind Systems A/S This e-mail is subject to our e-mail disclaimer statement. Please refer to www.vestas.com/legal/notice If you have received this e-mail in error please contact the sender. > -----Original Message----- > From: r-help-boun...@r-project.org [mailto:r-help-boun...@r-project.org] > On Behalf Of eliza botto > Sent: 23. marts 2014 03:02 > To: r-help@r-project.org > Subject: [R] points with-in boundaries of a map > > Dear UseRs, > I have a question regarding reading the coordinates within a country' map. I > drew map of ireland by using the following commands > library("maps") > library("mapproj") > map("world", "ireland") > map.axes() > You can clearly see the axis labelled. What is want to do is to draw lines > (both > vertically and horizontally ) at an interval of 0.5. Which means if x-axis > starts > from -10 then the first be on -10 and second on -9.5 and so on. Similar has to > be the case with y-axis. > Afterwards I only want to read the coordinates of the point falling with in > the > boundary of ireland. I spent quite sometime while going through the > previous posts but couldnt find the answer. > Thankyou very much in advance, > Elisa > > [[alternative HTML version deleted]] > > ______________________________________________ > 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. ______________________________________________ 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.