mapGriddedData: Produce maps of global gridded data at half degree resolution
In rworldmap: Mapping global data, vector and raster.

Description Usage Arguments Details Value Author(s) See Also Examples

Produce maps of global gridded data at half degree resolution

mapGriddedData(  dataset =          ""
               , nameColumnToPlot = "" 
               , numCats =          5  
               , catMethod =        "quantiles"   
               , colourPalette =    "heat"  
               , xlim =             c(-180,180)
               , ylim =             c(-80,90) 
               , mapRegion =  "world"   
               , addLegend =  TRUE
               , addBorders = 'coarse' 
               , borderCol =  'grey'
               , oceanCol =   NA
               , landCol =    NA
               , plotData =   TRUE
               , aspect =     1
               , lwd =        1
               )

`dataset`	gridded data either as a : SpatialGridDataFrame (R object defined in package sp) file name of a GridAscii file - this is an Esri format 2D R matrix or array (rows by columns)
`nameColumnToPlot`	name of column containing the data to plot
`numCats`	number of categories to put the data in, may be overidden if catMethod ='pretty'
`catMethod`	method for categorisation of data "pretty", "fixedWidth","diverging", "logFixedWidth","quantiles","categorical", or a numeric vector defining breaks
`colourPalette`	a string describing the colour palette to use, choice of : "palette" for the current palette a vector of valid colours, e.g. =c('red','white','blue') or output from RColourBrewer one of "heat", "diverging", "white2Black", "black2White", "topo", "rainbow", "terrain", "negpos8", "negpos9"
`xlim`	map extents c(west,east), can be overidden by mapRegion
`ylim`	map extents c(south,north), can be overidden by mapRegion
`mapRegion`	a country name from getMap()[['NAME']] or 'world','africa','oceania','eurasia','uk' sets map extents, overrides xlim,ylim
`addLegend`	whether to add a legend or not
`addBorders`	options for country borders, 'low','coarse' = low or coarse resolution, 'coasts' = coasts only, 'none' or NA for none
`borderCol`	the colour for country borders
`oceanCol`	a colour for the ocean if the grid values are NA
`landCol`	a colour to fill countries if the grid values are NA over land
`plotData`	whether to plotData, if FALSE a legend can be added on its own
`aspect`	aspect for the map, defaults to 1, if set to 'variable' uses same method as plot.Spatial in sp
`lwd`	line width for country borders

Plots a map of global half degree gridded data, allowing classification, colours and regions to be set.

Certain catMethod and colourPalette options go well together. e.g. "diverging" and "diverging", "categorical" and "rainbow"

invisibly returns a list containing the data and main options used for the map, the list can be passed to addMapLegend along with additional options to allow greater flexibility in legend creation.

andy south and matthew staines

classInt, RColorBrewer

## mapping continuous data
data(gridExData,envir=environment(),package="rworldmap")
gridExData <- get("gridExData")
mapGriddedData(gridExData)

## reclassing continuous data to categorical & mapping
data(gridExData,envir=environment(),package="rworldmap")
#find quartile breaks
cutVector <- quantile(gridExData@data[,1],na.rm=TRUE)
#classify the data to a factor
gridExData@data$categories <- cut( gridExData@data[,1]
                                      , cutVector, include.lowest=TRUE)
#rename the categories
levels(gridExData@data$categories) <- c('low', 'med', 'high', 'vhigh')
#mapping
mapGriddedData( gridExData, nameColumnToPlot= 'categories'
              , catMethod='categorical')