pcbs {GRASS}R Documentation

PCBs in an area of South Wales

Description

The pcbs data frame has 70 rows and 3 columns. It records contamination of the environment with polychlorinated biphenyls around the site of a large plant for the incineration of chemical wastes near Pontypool, South Wales.

Usage

data(pcbs)

Format

This data frame contains the following columns:

east
a numeric vector - UTM zone 30 eastings coordinates
north
a numeric vector - UTM zone 30 northings coordinates
pcbs
a numeric vector - standardised scores for seven types of PCB

Details

The original data were positioned in relation to National Grid coordinates, and have been reprojected to UTM zone 30, using the WGS84 ellipsoid.

Note

This dataset will only work if R is started from inside GRASS, choosing the location for the Pontypool PCBs data. GRASS installations differ in permissions needed to establish a new location, and system administrator privileges may be needed to create the Pontypool location. Information about the necessary metadataare as follows. The actual data may be accessed from R: data(pcbs).

projection
UTM
ellipsoid
WGS84
zone
30
north
77200
south
74500
west
68000
east
70200
nsres
25
ewres
25
rows
108
cols
88

Source

Bailey, T. C., Gatrell, A. C. 1995 Interactive Spatial Data Analysis (Longman, Harlow); pages 149-150, courtesy of Andrew Lovett, School of Environmental Sciences, University of East Anglia.

Examples

data(pcbs)
pcbs.o <- as.ordered(cut(pcbs$pcbs, labels=c("insignificant", "low",
"medium", "high", "crisis"), breaks=c(1,20,100,500,1000,5000),
include.lowest=TRUE))
table(pcbs.o)
plot(pcbs$east, pcbs$north, pch=unclass(pcbs.o), xlab="", ylab="", asp=1)
legend(x=c(67980, 68480), y=c(74710, 75180), pch=c(1:5), legend=levels(pcbs.o))


[Package GRASS version 0.3-7 Index]