Re: [R-sig-Geo] Specify color for "zero" raster values using levelplot

[Melanie Bacou]

Simply use the same palette as in the example: library(lattice) myPal <- read.table(sep="\t", text=" 155     29     32    Brown 238     36     37    Tomato 238     77     34    Tomato 250    143     35    Dark orange 254    215     24    Gold 214    223     47    Bitter lemon 188    218    112    Sulu 179    179    179    Dark gray 124    199    177    Keppel 105    202    229    Viking 72     156    211    Curious blue 69     101    173    Chetwode blue 58     86     164    Governor bay 58     72     155    Dark slate blue 44     46     118    Blue bell") myPal <- colorRampPalette(rgb(myPal[, 1:3], names=as.character(myPal$V4), maxColorValue=255)) x <- seq(pi/4, 5 * pi, length.out = 100) y <- seq(pi/4, 5 * pi, length.out = 100) r <- as.vector(sqrt(outer(x^2, y^2, "+"))) grid <- expand.grid(x=x, y=y) grid$z <- cos(r^2) * exp(-r/(pi^3)) levelplot(z~x*y, grid, cuts=14, col.regions=myPal(15), margin=FALSE) --Mel. On 05/17/2017 01:25 PM, Thiago V. dos Santos via R-sig-Geo wrote: Dear all, I am trying to change the color for zero values in a map produced using levelplot to plot a raster file. Specifically, I want to reproduce this figure: http://i.imgur.com/mjXxZhO.png, where a red to blue scale is used, but notice that zero values have been replaced by grey. As an example, let's use an adapted version of the August irradiation code from the rasterVis webpage: ################################ library(raster) library(ncdf4) library(rasterVis) ##Solar irradiation data from CMSAF old <- setwd(tempdir()) download.file('https://raw.github.com/oscarperpinan/spacetime-vis/master/data/SISmm2008_CMSAF.zip', 'SISmm2008_CMSAF.zip', method='wget') unzip('SISmm2008_CMSAF.zip') listFich <- dir(pattern='\\.nc') stackSIS <- stack(listFich) stackSIS <- stackSIS * 24 ##from irradiance (W/m2) to irradiation Wh/m2 idx <- seq(as.Date('2008-01-15'), as.Date('2008-12-15'), 'month') SISmm <- setZ(stackSIS, idx) names(SISmm) <- month.abb setwd(old) # Set color palette myTheme=rasterTheme(region=brewer.pal('RdBu', n=11)) Aug <- raster(SISmm, 8) meanAug <- cellStats(Aug, mean) levelplot(Aug - meanAug, par.settings = myTheme, margin=FALSE) ################################ In the example above, how can I replace the color of "zero values" with grey? Thanks, -- Thiago V. dos Santos PhD student Land and Atmospheric Science University of Minnesota _______________________________________________ R-sig-Geo mailing list R-sig-Geo@r-project.org https://stat.ethz.ch/mailman/listinfo/r-sig-geo

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