Thanks for this Arien,
Just can't get it to work though. I messed around a bit more yesterday
but couldn't find a way. No one else on the list replied. I have another
reason to want to do something similar, so I was hoping there was a work
around out there. Here is the data if you (or anyone else) can help.
load(file=url("ftp://200.23.34.16/simulacion/SPATIAL/chisgrid.rob"))
load(file=url("ftp://200.23.34.16/simulacion/SPATIAL//municipios.rob"))
#municipios was originally imported from a shapefile. The "dem" is a
coarse 1 km x 1km grid imported from GRASS 5.7. Both use UTM NAD27, but
the projections are not #set. The data represents the state of Chiapas
in Southern Mexico
image(chisgrid,"dem",col=terrain.colors(100))
plot(municipios,add=T)
#Gives what we wanted in base graphics
#But
spplot(municipios, "AREA", panel <- function(x,y,...){
sp.grid(chisgrid)
panel.polygonsplot(x,y,...)
})
#Doesn't
#and
municips <- list("sp.polygons", municipios)
spplot(chisgrid["dem"],sp.layout=municips)
#Draws them in the wrong order.
#As an aside, this is great fun with rgl and the students loved it. Can
anyone improve the code?
view3d<-function(grid=chisgrid,dem=1,drape=2,exag=3,pal=sp.theme()$regions$col){
fullgrid(grid)<-TRUE
y<-grid[[dem]]*exag
y[is.na(y)]<-0
dim(y)<-grid at grid@cells.dim
x <- grid at grid@cellsize[1]*(1:grid at grid@cells.dim[1])
z <-grid at grid@cellsize[2]*(1:grid at grid@cells.dim[2])
y2<-grid[[drape]]
y2[!is.na(y2)]<-as.numeric(cut( y2[!is.na(y2)],length(pal)))
y2[is.na(y2)]<-0
ylim <- range(y2)
ylen <- ylim[2] - ylim[1] + 1
pal<-c("black",pal)
col <- pal[ y2-ylim[1]+1 ] # assign colors to heights for each point
rgl.clear()
rgl.surface(x, z, y, color=col)
}
view3d(drape=1,pal=terrain.colors(100))
Duncan
Arien Lam wrote:
I stumbled there too.
A way is to customize the default panel function within spplot.
Try:
spplot(municipios, "yourvariable", panel <- function(x,y,...){
sp.grid(chisgrid)
panel.polygonsplot(x,y,...)
})
Regards, Arien
Duncan Golicher schreef:
Many thanks to everyone involved in putting together the excelent sp package. I have just used for teaching a brief intro to applied geostats with gstat. Students found life much easier than a year ago when I had to try to explain a less structured approach to the data. A simple question arose after the class. According to the spplot documentation "for grids and polygons sp.layout is drawn afterwards (so the item will not be overdrawn by the grid and/or polygon)". So in this example we expected a DEM to be drawn first, then municipal boundaries.
> class(municipios)
[1] "SpatialPolygonsDataFrame"
> class(chisgrid)
[1] "SpatialPixelsDataFrame"
municips <- list("sp.polygons", municipios)
spplot(chisgrid["dem"],sp.layout=municips)
The municipal boundaries are drawn first then overdrawn by the DEM,
which was not what we expected or wanted. I couldn't find how to
avoid this, apart from the simple solution of ..
image(chisgrid,col=terrain.colors(20))
plot(municipios,add=T)
instead of spplot.The figures on http://r-spatial.sourceforge.net
all appear to have the grid drawn first. Is there a way to reverse this?
Duncan
Dr Duncan Golicher Ecologia y Sistematica Terrestre Conservaci?n de la Biodiversidad El Colegio de la Frontera Sur San Cristobal de Las Casas, Chiapas, Mexico Email: dgoliche at sclc.ecosur.mx Tel: 967 674 9000 ext 1310 Fax: 967 678 2322 Celular: 044 9671041021 United Kingdom Skypein; 020 7870 6251 Skype name: duncangolicher Download Skype from http://www.skype.com