rasterVis (version 0.21)

hovmoller-methods: Hovmoller plots

Description

Hovmoller plots of Raster objects.

Usage

## S3 method for class 'RasterStackBrick':
hovmoller(object, dirXY=y, FUN=mean, 
digits=2, xlab='Direction', ylab='Time',
par.settings=rasterTheme(), xscale.components=xscale.raster,
add.contour=FALSE, labels=FALSE, region=TRUE, ...)

docType

methods

Details

Extracted from wikipedia: "A Hovmöller diagram is a commonly used way of plotting meteorological data to highlight the role of waves. The axes of a Hovmöller diagram are typically longitude or latitude (abscissa or x-axis) and time (ordinate or y-axis) with the value of some field represented through color or shading." The direction defined by dirXY and the function FUN allows for a variety of diagrams with this method.

References

• Hovmoller, E. 1949. The trough and ridge diagram. Tellus 1, 62–66.

http://www.mmm.ucar.edu/episodes/Hovmoller/noJS/hovm200707.htm http://www.star.nesdis.noaa.gov/sod/sst/squam/L4/l4_delsst_hovmoller.htm http://www.esrl.noaa.gov/psd/map/clim/sst.shtml

See Also

levelplot, zonal, panel.2dsmoother

Examples

##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

## Latitude as default
hovmoller(SISmm, xlab='Latitude')

## With contour lines and labels
hovmoller(SISmm, labels=TRUE, add.contour=TRUE,
          xlab='Latitude')

## Smooth color regions with latticeExtra::panel.2dsmoother
hovmoller(SISmm, panel=panel.2dsmoother, n=1000,
          labels=FALSE, add.contour=TRUE,
          xlab='Latitude')

## Using a function of coordinates
hovmoller(SISmm, dirXY=sqrt(x^2+y^2))

library(zoo)

url <- "ftp://ftp.wiley.com/public/sci_tech_med/spatio_temporal_data/"
sst.dat = read.table(paste(url, "SST011970_032003.dat", sep=''), header = FALSE) 
sst.ll = read.table(paste(url, "SSTlonlat.dat", sep=''), header = FALSE)

spSST <- SpatialPointsDataFrame(sst.ll, sst.dat)
gridded(spSST) <- TRUE
proj4string(spSST) = "+proj=longlat +datum=WGS84"
SST <- brick(spSST)

idx <- seq(as.Date('1970-01-01'), as.Date('2003-03-01'), by='month')
idx <- as.yearmon(idx)
SST <- setZ(SST, idx)
names(SST) <- as.character(idx)
hovmoller(SST, panel=panel.levelplot.raster,
          xscale.components=xscale.raster.subticks,
          interpolate=TRUE, par.settings=RdBuTheme)