Some quick ideas... One very easy way would be to round them all to integer degrees and remove the duplicates - or even just let the duplicates overwrite each other in the plot.
A step up from that would be to create a matrix at some resolution (e.g. 180 x 360 for a 1 degree global grid) and count the number of points that fall into each matrix cell. Then plot those points with symbol color or size to represent frequency categories. If you want to get fancy and look for "natural" spatial clusters of points in your data there are a number of packages that can help you: http://cran.r-project.org/web/views/Spatial.html Hope this helps. Michael On 14 October 2010 19:32, ogbos okike <ogbos.ok...@gmail.com> wrote: > Hi everybody, > I have a huge longitude and latitude data. I have used raster package to > get the since of its global distribution. But I wish to display the > information using a few points on the world map. > > The data is of the form: > 95.2156 0.8312 > -65.3236 -3.3851 > -65.2364 -3.2696 > -65.2349 -3.2679 > 164.7025 -17.6404 > 148.8214 -4.8285 > -67.6568 2.6477 > -73.4833 -0.2350 > 40.9587 -16.8655 > -61.6474 8.1179 > 93.3401 -0.2755 > 119.9011 -17.1733 > -69.7640 1.1245 > -149.3088 -20.0035 > 177.8753 -3.4200 > -67.5590 3.0133 > -21.9331 15.4684 > 120.2656 -17.6166 > 165.9368 -17.3888 > 164.7335 -17.6953 > -74.0017 -1.8623 > -71.1195 -3.3562 > 130.1496 -11.5775 > > > I am thinking of a way of handling that data in such a way that they can be > represented by fewer points when plotted on the map. I have tried using > factor method but didn't get any way. > > Thank you for any idea > Best > Ogbos > > [[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.
