Re: [R] control margin when plotting polygons? On Fri, 11 May 2007, Shengde Liang wrote: >  > Hello everyone, >  > I have some difficulties on controling the margin of a plot. > For example, the following code from the help of maptools: >  > library(maptools) > xx <- readShapePoly(system.file("shapes/sids.shp", package="maptools")[1],  > IDvar="FIPSNO", proj4string=CRS("+proj=longlat +ellps=clrk66")) > plot(xx, border="blue", axes=TRUE, las=1) >  > There is a lot of white margin on the bottom and top of the plot and I  > want to get rid of it. I used option "usr", but it does not make any  > change. >  > plot(xx, border="blue", axes=TRUE, las=1,usr=c(-85,-75,33,39)) > par(usr=c(-85,-75,33,39)) > plot(xx,border="blue",axes=T,las=1) >  > Option "ylim" does not work either. This plot method is more complicated than you can see for geographical  coordinates, because the y axis is streched. But the real cause of your  problem is the shape of the plot device. If you compare the output of: png("default_size.png", pointsize=8) par(mar=c(3,3,1,1)) plot(xx, border="blue", axes=TRUE, las=1) dev.off() png("portrait_size.png", width=300, height=480, pointsize=8) par(mar=c(3,3,1,1)) plot(xx, border="blue", axes=TRUE, las=1) dev.off() png("landscape_size.png", width=480, height=300, pointsize=8) par(mar=c(3,3,1,1)) plot(xx, border="blue", axes=TRUE, las=1) dev.off() you can see that the amount of the plotting area covered by the map can be  controlled to reduce the white space. You can also use par(mar=c()) to remove margins, but then possibly without the axes, or at least watching the effects of las=. The GE_SpatialGrid()   function also sets up cropping sizes for export of maps in geographical coordinates as image overlays for Google Earth, and may contain some ideas. >  > Anyone has any idea how to do it? The answers vary a great deal depending on needs, and are seldom  completely general. For publication, editing externally may be an option. Roger >  > Thanks a lot. >  > Best, >  > Shengde Liang >  > ______________________________________________ > R-help@stat.math.ethz.ch 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. >  --  Roger Bivand Economic Geography Section, Department of Economics, Norwegian School of Economics and Business Administration, Helleveien 30, N-5045 Bergen, Norway. voice: +47 55 95 93 55; fax +47 55 95 95 43 e-mail: Roger.Bivand@nhh.no ______________________________________________ R-help@stat.math.ethz.ch 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.