levelplot-methods: Level and contour plots of Raster objects.

Description

Level and contour plots of Raster objects with lattice methods and marginal plots with grid objects.

Usage

## S3 method for class 'Raster,missing':
levelplot(x, data=NULL, layers,
            margin=!(any(is.factor(x))), FUN.margin=mean, 
            maxpixels=1e5,
            par.settings=rasterTheme(),
            between=list(x=0.5, y=0.2),
            as.table=TRUE,
            xlab='', ylab='', main='',
            names.attr,
            scales=list(), scales.margin=NULL,
            xscale.components=xscale.raster,
            yscale.components=yscale.raster,
            zscaleLog=NULL,
            colorkey=list(space='right'),
            panel=panel.levelplot,
            contour=FALSE, region=TRUE, labels=FALSE,
            ...)
## S3 method for class 'Raster,missing':
contourplot(x, data=NULL, layers, ...)

Arguments

docType

methods

Details

The result of the levelplot method is similar to the spplot method for Raster objects defined in the raster package. However, this method does not use the spplot of the sp package and, therefore, no conversion between classes is needed.

The contourplot method is a wrapper for levelplot with the next additional default settings: cuts=7, labels=TRUE, contour=TRUE, pretty=TRUE, region=TRUE and colorkey=TRUE (see the help of contourplot for details.)

levelplot displays categorical data with a convenient legend. You should use ratify to define a layer as a categorical variable. It is able to display multilayer categorical rasters only if they share the same RAT (Raster Attribute Table). levelplot is not able to display multilayer rasters with factor and numeric layers. See ratify and the examples below for details.

Examples

Run this code

f <- system.file("external/test.grd", package="raster")
r <- raster(f)
levelplot(r)

## With subticks
levelplot(r, xscale.components=xscale.raster.subticks,
             yscale.components=yscale.raster.subticks)

levelplot(r, xscale.components=xscale.raster.subticks,
             yscale.components=yscale.raster.subticks,
             scales=list(x=list(rot=30, cex=0.8)))

## defining the scales for the marginal plot
levelplot(r, scales.margin=list(x=c(100, 600), y=c(100, 1000)))
## if a component of the list is null, it is internally calculated
levelplot(r, scales.margin=list(x=c(100, 1000)))

## log-scale
levelplot(r^2, zscaleLog=TRUE, contour=TRUE)

s <- stack(r, r+500, r-500)
levelplot(s, contour=TRUE)
contourplot(s, labels=list(cex=0.4), cuts=12)

levelplot(s, names.attr=c('R', 'R + 500', 'R - 500'))

## Add a layer of sampling points
## and change the theme
pts <- sampleRandom(r, size=20, sp=TRUE)

## Using +.trellis and layer from latticeExtra
levelplot(r, par.settings = BTCTheme) + layer(sp.points(pts, col = 'red'))
contourplot(r, labels = FALSE) + layer(sp.points(pts, col = 'red'))

## or with a custom panel function
levelplot(r, par.settings=BTCTheme,
          panel=function(...){
            panel.levelplot(...)
            sp.points(pts, col='red')
            })


## Categorical data
r <- raster(nrow=10, ncol=10)
r[] = 1
r[51:100] = 3
r[3:6, 1:5] = 5
r <- ratify(r)
     
rat <- levels(r)[[1]]
rat$landcover <- c('Pine', 'Oak', 'Meadow')
levels(r) <- rat
r

levelplot(r, col.regions=c('palegreen', 'midnightblue', 'indianred1'))

r2 <- raster(r)
r2[] = 3
r2[51:100] = 1
r2[3:6, 1:5] = 5

r3 <- init(r, function(n)sample(c(1, 3, 5), n, replace=TRUE))

## Multilayer categorical Raster* are displayed only if their RATs are the same
levels(r2) <- levels(r3) <- levels(r)

s <- stack(r, r2, r3)
names(s) <- c('A', 'B', 'C')

levelplot(s)


##Solar irradiation data from CMSAF
##Data available from http://www.box.net/shared/rl51y1t9sldxk54ogd44

old <- getwd()
##change to your folder...
setwd('CMSAF')
listFich <- dir(pattern='2008')
stackSIS <- stack(listFich)
stackSIS <- stackSIS*24 ##from irradiance (W/m2) to irradiation Wh/m2
setwd(old)

idx <- seq(as.Date('2008-01-15'), as.Date('2008-12-15'), 'month')

SISmm <- setZ(stackSIS, idx)
names(SISmm) <- month.abb

levelplot(SISmm)

levelplot(SISmm, layers=1, FUN.margin=median, contour=TRUE)