The first thing to do is to find out the class of the object you are plotting. For example, in this example:
library(maptools) xx <- readShapePoints(system.file("shapes/baltim.shp", package="maptools")[1]) plot(xx) Then: > class(xx) [1] "SpatialPointsDataFrame" attr(,"package") [1] "sp" This indicates that you are using the plot() function from the sp package. > find('plot') [1] "package:sp" "package:graphics" The plot function in the sp package is built on the plot function in the graphics package, that is, the plot() that is included with R. This implies that the possible arguments include those of the basic plot function. For example: plot(xx, cex=2) plot(xx, cex=2, col='red', pch=4) Exactly what the additional arguments do depends on the class of the object you're plotting. For lines objects, see ?lines For polygon objects, see ?polygons For points objects, see ?points (that list is an abbreviated version of Table 3.2 in the book Applied Spatial Data Analysis with R, by Bivand, Pebesma, and Gomez-Rubio; get a copy if you can!) Final suggestion; if you are using the "read" functions from maptools as in the example above, I would suggest installing the rgdal package and using readOGR() instead. I think you will be better off in the long run (and I'm pretty sure this is what the experts have been recommending). -Don -- Don MacQueen Lawrence Livermore National Laboratory 7000 East Ave., L-627 Livermore, CA 94550 925-423-1062 On 12/25/14, 1:43 AM, "kun17" <kzh...@geo.ecnu.edu.cn> wrote: >Hi all, > >I want to use maptools to plot map, there are many plot examples in the >document, but I can not find the usage explaination for plot function as >well as the possible parameters. > >Could someone give me advice? > >Kun > > > > > > >-- >View this message in context: >http://r-sig-geo.2731867.n2.nabble.com/maptools-issue-tp7587580.html >Sent from the R-sig-geo mailing list archive at Nabble.com. > >_______________________________________________ >R-sig-Geo mailing list >R-sig-Geo@r-project.org >https://stat.ethz.ch/mailman/listinfo/r-sig-geo _______________________________________________ R-sig-Geo mailing list R-sig-Geo@r-project.org https://stat.ethz.ch/mailman/listinfo/r-sig-geo