vector.R

  ##################################################################
  ## Source code for the book: "Displaying time series, spatial and
  ## space-time data with R"
  
  ## Copyright (C) 2013-2012 Oscar Perpiñán Lamigueiro
  
  ## This program is free software you can redistribute it and/or modify
  ## it under the terms of the GNU General Public License as published
  ## by the Free Software Foundation; either version 2 of the License,
  ## or (at your option) any later version.
   
  ## This program is distributed in the hope that it will be useful, but
  ## WITHOUT ANY WARRANTY; without even the implied warranty of
  ## MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  ## General Public License for more details.
   
  ## You should have received a copy of the GNU General Public License
  ## along with this program; if not, write to the Free Software
  ## Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA
  ## 02111-1307, USA.
  ####################################################################

  ##################################################################
  ## Initial configuration
  ##################################################################
  ## Clone or download the repository and set the working directory
  ## with setwd to the folder where the repository is located.

##################################################################
## Vector fields
##################################################################

  library(raster)
  library(rasterVis)
  
  wDir <- raster('data/wDir')/180*pi
  wSpeed <- raster('data/wSpeed')
  windField <- stack(wSpeed, wDir)
  names(windField) <- c('magnitude', 'direction')

##################################################################
## Arrow plot
##################################################################

pdf(file="figs/vectorplot.pdf")
  vectorplot(windField, isField=TRUE, par.settings=BTCTheme(),
             colorkey=FALSE, scales=list(draw=FALSE))
dev.off()

##################################################################
## Streamlines
##################################################################

pdf(file="figs/streamplot.pdf")
  myTheme <- streamTheme(region=rev(brewer.pal(n=4, name='Greys')),
                                      symbol=BTC(n=9, beg=20))
  streamplot(windField, isField=TRUE,
             par.settings=myTheme,
             droplet=list(pc=12),
             streamlet=list(L=5, h=5),
             scales=list(draw=FALSE),
             panel=panel.levelplot.raster)
dev.off()