rworldmap (version 1.3-8)

mapGriddedData: Produce maps of global gridded data at half degree resolution

Description

Produce maps of global gridded data at half degree resolution

Usage

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
)

Value

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.

Arguments

dataset

gridded data either as a :

1. SpatialGridDataFrame (R object defined in package sp)

2. file name of a GridAscii file - this is an Esri format

3. 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 :

1. "palette" for the current palette

2. a vector of valid colours, e.g. =c('red','white','blue') or output from RColourBrewer

3. 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

Author

andy south #@importFrom maptools readAsciiGrid

Details

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"

See Also

classInt, RColorBrewer

Examples

## 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')