2009/5/29 Roger Bivand <roger.biv...@nhh.no>: > On Thu, 28 May 2009, brwin...@aol.com wrote: > >> Good Morning: >> >> I need to construct a set of Thiessen Polygons centered around >> approximately 4500 longlat positions in the US. After searching the R site, >> I was going to attempt to use the arealsubPolygons function in the >> hydrosanity package. I am using a Windows system. >> >> When attempting to call the package I get the following error messages >> under both R2.8.1 and R2.9.0. >> ################################################################## >>> >>> require(hydrosanity) >> >> Loading required package: hydrosanity >> Loading required package: playwith >> Loading required package: lattice >> Loading required package: cairoDevice >> Error in inDL(x, as.logical(local), as.logical(now), ...) : >> unable to load shared library >> 'C:/PROGRA~1/R/R-28~1.1/library/cairoDevice/libs/cairoDevice.dll': >> LoadLibrary failure: The specified module could not be found. >> >> >> Error: package 'cairoDevice' could not be loaded >> ################################################################### >> I have tried downloading the package and it's dependencies from several >> locations and get the same errors each time. >> >> Any suggestions with respect to this package or others that I might use >> to >> construct my polygons would be appreciated. I need a set of polygons >> that >> cover the entire US county polygon. > > The package description does say that it is "under development and should > not be considered stable", seems honest. Look at the code in its URL: > > http://code.google.com/p/hydrosanity/source/browse/trunk/R/spatial_functions.R > > find the function and its dependencies, load sp first, and probably a matrix > of boundary coordinates for a representation that has a coercion method to > gpc.poly, your point matrix, a vector of IDs, and source the function > locally. That avoids resolving all the dependencies needed for the GUI in > the package, and ought to work. Watch the min.area.pct= argument as small > polygons may go away. > > Should work with some tweaking.
I tried library(sp) library(tripack) library(gpclib) foo <- arealSubPolygons(state.center, IDs = state.name) class(foo) [1] "SpatialPolygons" But I can't seem to plot the result... spplot(foo) Error in function (classes, fdef, mtable) : unable to find an inherited method for function "spplot", for signature "SpatialPolygons" Note also that you can construct Thiessen / Voronoi Polygons for plotting with the tileplot function in latticeExtra: library(latticeExtra) tileplot(x ~ x * y, state.center, border = "black", points=FALSE) See the code for panel.voronoi for how it is done (it has two implementations, based on either tripack or deldir). Hope that helps -Felix -- Felix Andrews / 安福立 Post-Doctoral Fellow Integrated Catchment Assessment and Management (iCAM) Centre Fenner School of Environment and Society [Bldg 48a] The Australian National University Canberra ACT 0200 Australia M: +61 410 400 963 T: + 61 2 6125 1670 E: felix.andr...@anu.edu.au CRICOS Provider No. 00120C -- http://www.neurofractal.org/felix/ _______________________________________________ R-sig-Geo mailing list R-sig-Geo@stat.math.ethz.ch https://stat.ethz.ch/mailman/listinfo/r-sig-geo