No, it's me, I only read half of your question. Try something like
spplot(spdf["dist"], sp.layout=list("sp.polygons", river))
or the incremental build, in lattice style, of
spplot(spdf["dist"])
library(lattice)
spplot(spdf["dist"])
trellis.focus("panel", 1, 1)
sp.polygons(river)
trellis.unfocus()
which will put the river on the foreground. This can be obtained in a
single pass with
spplot(spdf["dist"], sp.layout=list("sp.polygons", river, first=FALSE))
I slowly get the feeling that spplot needs a bit more documentation, or
examples.
--
Edzer
Ryan Anderson wrote:
That likely gives me the control over the color ramp that I am looking
for, but I still have trouble plotting the vector layer over the top of
the resulting image plot.
If I do:
spplot(spdf["dist"],col.regions=heat.colors(400), at = 0:10/10)
plot(river, add = TRUE)
I still get the plot.new has not been called yet error after I attempt to
add the river data. What am I doing wrong?
Thanks,
Ryan
Ryan, you're probably looking for something like
spplot(spdf["dist"],col.regions=heat.colors(400), at = 0:10/10)
spplot is a wrapper around lattice functions for spatial data, and tries
to pass on all the lattice controls.
--
Edzer
Ryan Anderson wrote:
I have some gridded spatial data that I want to plot with a vector
overlay
on top. The following reproducible code makes a figure similar to the
one
I am ultimately trying to produce:
library(sp)
library(fields)
data(meuse.grid)
data(meuse.riv)
coords <- SpatialPixels(SpatialPoints(meuse.grid[, c("x","y")]))
spdf <- SpatialPixelsDataFrame(coords, meuse.grid)
fullgrid(spdf)<-TRUE
river<-SpatialPolygons(list(Polygons(list(Polygon(meuse.riv)),"meuse.riv")))
par(mar = c(5,5,5,8), col.axis = 1)
ramp = heat.colors(400)
image(spdf, "dist", axes = TRUE, col = ramp)
plot(river, add = TRUE)
zvals<-spdf$dist
zvals<-zvals[!is.na(zvals)]
image.plot(zlim = c(min(zvals), max(zvals)), nlevel = 256, legend.only =
TRUE, col = ramp)
I need more control over the legend and the color ramp than I know how
to
achieve with this code. I can create the plot I want with levelplot by
setting the 'at' component 'colorkey', but when I try to overlay the
vector file I get an error. Here is a simplified version of the code I
tried:
#try a levelplot
library(lattice)
x11()
par(mar = c(5,5,5,8))
x<-spdf$x
y<-spdf$y
z<-spdf$dist
levelplot(z~x+y)
plot(river, add = TRUE)
#Gives Error in polygon(x = x, y = y, border = border, col = col, lty =
#lty, :
# plot.new has not been called yet
I need to either find a way to control the mapping of data values to the
color ramp more precisely in my call to image or image.plot or to find a
way to plot a ploygon over the top of a levelplot.
My color ramp goals more specifically: my grid contains both positive
and
negative values, and they are not necessarily symmetrically distributed
around zero. I want to plot them so that zero is white, negative values
are symbolized with a ramp from white to blue (with darker shades for
lower values) and positive values are symbolized with a ramp from white
to
red (with darker shades for higher values).
Thanks for your help!
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--
Edzer Pebesma
Institute for Geoinformatics (ifgi), University of Münster,
Weseler Straße 253, 48151 Münster, Germany. Phone: +49 251
8333081, Fax: +49 251 8339763 http://ifgi.uni-muenster.de/
--
Edzer Pebesma
Institute for Geoinformatics (ifgi), University of Münster,
Weseler Straße 253, 48151 Münster, Germany. Phone: +49 251
8333081, Fax: +49 251 8339763 http://ifgi.uni-muenster.de/
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