OsloTransect: Oslo Transect Data
In rrcov: Scalable Robust Estimators with High Breakdown Point

OsloTransect

R Documentation

Oslo Transect Data

Description

The oslo Transect data set contains 360 samples of different plant species collected along a 120 km transect running through the city of Oslo, Norway.

Usage

data(OsloTransect)

Format

A data frame with 360 observations on the following 38 variables.

X.ID: a numeric vector, unique ID of the sample
X.MAT: a factor with levels BBA BIL BWO FER MOS ROG SNE STW TWI
XCOO: a numeric vector, X coordinate
YCOO: a numeric vector, Y coordinate
XCOO_km: a numeric vector
YCOO_km: a numeric vector
X.FOREST: a factor with levels BIRSPR MIXDEC PINE SPRBIR SPRPIN SPRUCE
DAY: a numeric vector
X.WEATHER: a factor with levels CLOUD MOIST NICE RAIN
ALT: a numeric vector
X.ASP: a factor with levels E FLAT N NE NW S SE SW W
X.GRVEG: a factor with levels BLGR BLLY BLMOLI BLUE BLUGRA GRAS GRBLU GRFE GRMO LYLI MIX MOGR MOSS
X.FLITHO: a factor with levels CAMSED GNEID_O GNEIS_O GNEIS_R MAGM MICSH
Ag_ppb: a numeric vector
As_ash: a numeric vector
B: a numeric vector
Ba: a numeric vector
Ca: a numeric vector
Cd: a numeric vector
Co: a numeric vector
Cr: a numeric vector
Cu: a numeric vector
Fe: a numeric vector
Hg_ppb: a numeric vector
K: a numeric vector
La: a numeric vector
LOI: a numeric vector
Mg: a numeric vector
Mn: a numeric vector
Mo: a numeric vector
Ni: a numeric vector
P: a numeric vector
Pb: a numeric vector
S: a numeric vector
Sb: a numeric vector
Sr: a numeric vector
Ti: a numeric vector
Zn: a numeric vector

Details

Samples of different plant species were collected along a 120 km transect running through the city of Oslo, Norway (forty samples each of leaves, needles,roots or barks of several plant species), and the concentrations of 25 chemical elements for the sample materials are reported. The factors that influenced the observed element concentrations in the sample materials were investigated. This data set was used in Todorov and Filzmoser (2007) for illustration of the robust statistics for one-way MANOVA implemented in the function Wilks.test.

Source

REIMANN,C., ARNOLDUSSEN,A., BOYD,R., FINNE,T.E., NORDGULEN,Oe., VOLDEN,T. and ENGLMAIER,P. (2006) The Influence of a city on element contents of a terrestrial moss (Hylocomium splendens), The Science of the Total Environment 369 419–432.

REIMANN,C., ARNOLDUSSEN,A., BOYD,R., FINNE,T.E., KOLLER,F., NORDGULEN,Oe., and ENGLMAIER,P. (2007) Element contents in leaves of four plant species (birch, mountain ash, fern and spruce) along anthropogenic and geogenic concentration gradients, The Science of the Total Environment 377 416–433.

REIMANN,C., ARNOLDUSSEN,A., FINNE,T.E., KOLLER,F., NORDGULEN,Oe., and ENGLMAIER,P., (2007) Element contents in birch leaves, bark and wood under different anthropogenic and geogenic conditions, Applied Geochemistry, 22 1549–1566.

References

Todorov V. and Filzmoser P. (2007) Robust statistic for the one-way MANOVA, submetted to the Journal of Environmetrics.

Examples

data(OsloTransect)
str(OsloTransect)

##
##  Log-transform the numerical part of the data, 
##  choose the desired groups and variables and 
##  perform the classical Wilks' Lambda test
##
OsloTransect[,14:38] <- log(OsloTransect[,14:38])
grp <- OsloTransect$X.FLITHO
ind <- which(grp =="CAMSED" | grp == "GNEIS_O" |
    grp == "GNEIS_R" | grp=="MAGM")
(cwl <- Wilks.test(X.FLITHO~K+P+Zn+Cu,data=OsloTransect[ind,]))

##
## Perform now the robust MCD based Wilks' Lambda test. 
##  Use the already computed multiplication factor 'xd' and 
##  degrees of freedom 'xq' for the approximate distribution.
##

xd <- -0.003708238
xq <- 11.79073
(mcdwl <- Wilks.test(X.FLITHO~K+P+Zn+Cu,data=OsloTransect[ind,], 
    method="mcd", xd=xd, xq=xq))

rrcov documentation built on May 29, 2024, 1:13 a.m.