x = 10 # center x y = 10 # center y n = 100 # nr of pts r = 5 # radius pts = seq(0, 2 * pi, length.out = n) plot(sin(pts), cos(pts), type = 'l', asp = 1) # test require(sp) xy = cbind(x + r * sin(pts), y + r * cos(pts)) sl= SpatialLines(list(Lines(list(Line(xy)), "line"))) plot(sl, add=FALSE, col = 'red', axes=T )
this draws a circle as a line; if you want a filled polygon, I'd replace every instance of Line with Polygon (but mind the s). On 11/06/2012 09:30 PM, Wouter Steenbeek wrote: > I have a plot with several layers of SpatialPoints and Polygons. They are all > projected and in the correct CRS, so my map looks like it should. I now want > to draw a circle with a radius x on a part of this map. This should not just > be a circle, but be in the correct projection (so that I can change radius x > to whatever I desire, and the circle is drawn correctly on scale, and > slightly "distorted" dependent on my zoom of the map). > > How do I do this? Thanks! > > (I understand that I should define a new polygon and "plot(..., add=T)" that > to my map. But how do I make such a polygon? I don't quite understand the > "polygon" function in the 'graphics' package, if that's even the correct one > to use. Seeing an example would help.) > > _______________________________________________ > R-sig-Geo mailing list > R-sig-Geo@r-project.org > https://stat.ethz.ch/mailman/listinfo/r-sig-geo > -- Edzer Pebesma Institute for Geoinformatics (ifgi), University of Münster Weseler Straße 253, 48151 Münster, Germany. Phone: +49 251 8333081, Fax: +49 251 8339763 http://ifgi.uni-muenster.de http://www.52north.org/geostatistics e.pebe...@wwu.de _______________________________________________ R-sig-Geo mailing list R-sig-Geo@r-project.org https://stat.ethz.ch/mailman/listinfo/r-sig-geo
