create an Hexagonal grid

There is the hexbin package available through Bioconductor.  It uses grid graphics I believe.

If you want a base graphics solution, or just more hands on control (and using only CRAN packages), then check out the last example on the help page for the my.symbols function in the TeachingDemos package.

Gregory (Greg) L. Snow Ph.D.
Statistical Data Center
Intermountain Healthcare
greg.snow at imail.org
801.408.8111


> -----Original Message-----
> From: r-sig-geo-bounces at stat.math.ethz.ch [mailto:r-sig-geo-
> bounces at stat.math.ethz.ch] On Behalf Of gianni lavaredo
> Sent: Wednesday, September 15, 2010 9:29 AM
> To: r-sig-geo at stat.math.ethz.ch
> Subject: [R-sig-Geo] create an Hexagonal grid
> 
> Dear reseacher,
> 
> is there a way to create an Hexagonal grid with R?
> 
> thanks
> Gianni
> 
> 	[[alternative HTML version deleted]]
> 
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Dear Gianni,

a good reference is the book "Applied Spatia lData Analysis with R", where there is an example in the Chapter "6.4 Hexagonal Grids" on page 137. Try this example using the test data set "meuse":

library(sp)
data(meuse.grid)
HexPts <- spsample(meuse.grid, type = "hexagonal", cellsize = 200)
spplot(meuse.grid["dist"], sp.layout = list("sp.points", HexPts, col = 1))
HexPols <- HexPoints2SpatialPolygons(HexPts)
df <- as.data.frame(meuse.grid)[overlay(meuse.grid, HexPts), ]
HexPolsDf<-SpatialPolygonsDataFrame(HexPols, df, match.ID = FALSE)
spplot(HexPolsDf["dist"])

More details in the above mentioned (very helpful) book. According to the book, there are no classes for hexagonal grids but some useful funtions to generate and plot them.

Good luck!

Nils

Gesendet: Mittwoch, 15. September 2010 17:29
Bis: r-sig-geo at stat.math.ethz.ch
Betreff: [R-sig-Geo] create an Hexagonal grid

Dear reseacher,

is there a way to create an Hexagonal grid with R?

thanks
Gianni

        [[alternative HTML version deleted]]

_______________________________________________
R-sig-Geo mailing list
R-sig-Geo at stat.math.ethz.ch
https://stat.ethz.ch/mailman/listinfo/r-sig-geo

There is the hexbin package available through Bioconductor.  It uses 
grid graphics I believe.

If you want a base graphics solution, or just more hands on control (and 
using only CRAN packages), then check out the last example on the help 
page for the my.symbols function in the TeachingDemos package.

For sp objects, see the "hexagonal" type in spsample(), the low-level 
sp:::genHexGrid(), and HexPoints2SpatialPolygons():

hpts <- sp:::genHexGrid(dx=0.1, ll=c(0, 0), ur=c(1, 1))
pols <- HexPoints2SpatialPolygons(SpatialPoints(hpts))
plot(pols)

Hope this helps,

Roger

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 at nhh.no