Set up

• start RGui (from the desktop shortcut)
• to copy R-code into R:
  • select the code (in a Courier font like this) by left-clicking and dragging the mouse over it
  • press ctrl-C to copy
  • press alt-Tab to switch to R
  • press ctrl-V to paste into R (at the command prompt)
  • press alt-Tab to get back here

Download and open an existing data set

• Summit Cr. fluvial geomorph data [sumcr.csv] -- download and save to working directory
  
  sumcr <- read.csv("sumcr.csv")
   

• get some summary statistics for the data set
  
  summary(sumcr)
   

• plot water-surface width vs. cumulative length downstream
  
  attach(sumcr)
  plot(CumLen, WidthWS)
   

• add a summarizing curve
  
  lines(lowess(CumLen, WidthWS), col="red")
   

• get a matrix scatter plot of large world cities data [cities.csv]
  
  cities <- read.csv("cities.csv")
  plot(cities[,2:12])
   

• Oregon climate station data [orstationc.csv]
  
  orclimate <- read.csv("orstationc.csv", as.is=TRUE)
  attach(orclimate)
  plot(elev,tann)
  text(elev,tann,labels=station, cex=0.7)

A simple map-drawing script

Oregon county outlines:  (orcounty [.dbf] [.sbn] [.sbx] [.shp] [.shx])

• # simple maps of Oregon county data
  # uses shapefiles and maptools library
  library(maptools) # also load the sp package
  library(RColorBrewer)
   
• # read a shape file with attached attribute data
  orcounty.shp <- readShapePoly(file.choose())
   
• # turn plot history on and run graphics demos
   
• # equal-frequency class intervals
  plotvar <- orcounty.shp@data$AREA
  nclr <- 8
  plotclr <- brewer.pal(nclr,"BuPu")
  #plotclr <- plotclr[nclr:1] # reorder colors if appropriate
  brks <- round(quantile(plotvar, probs=seq(0,1,1/(nclr))), digits=1)
  colornum <- findInterval(plotvar, brks, all.inside=T)
  colcode <- plotclr[colornum]
  table(colornum)
  brks
  
  plot(orcounty.shp, xlim=c(-125, -114), ylim=c(42,47))
  plot(orcounty.shp, col=colcode, add=T)
  text(-120,46.5,"Equal-Frequency Class Intervals")
  legend(-117, 44, legend=leglabs(round(brks, digits=1)),
       fill=plotclr, cex=0.6, bty="n")
   
• # equal-width class intervals
  plotvar <- orcounty.shp@data$AREA
  nclr <- 8
  plotclr <- brewer.pal(nclr,"BuPu")
  #plotclr <- plotclr[nclr:1] # reorder colors if appropriate
  brks <- round(seq(min(plotvar),max(plotvar),
       by=((max(plotvar)-min(plotvar))/nclr), digits=1))
  colornum <- findInterval(plotvar, brks, all.inside=T)
  colcode <- plotclr[colornum]
  
  plot(orcounty.shp, xlim=c(-125, -114), ylim=c(42,47))
  plot(orcounty.shp, col=colcode, add=T)
  text(-120,46.5,"Equal-Width Class Intervals")
  legend(-117, 44, legend=leglabs(round(brks, digits=1)),
       fill=plotclr, cex=0.6, bty="n")
   

Some further examples with the built-in data sets

# turn plot history on and run graphics demos
windows(record=T)  # open a graphics window and records plots

demo(graphics)
demo(persp)

 

# look at the built-in data set "quakes"
summary(quakes)
attach(quakes)
plot(long, lat)

hist(depth)

hist(mag)

detach(quakes)

[back to topics and examples] [Geog 4/517] [Geog. 4/517 lectures]