Weed95 {gcKrig}

Counts of Weed Plants on a Field

Description

The weed species Viola Arvensis was counted within circular frames each of area 0.25 square meter except for 10 missing sites in the first row, from a 20 by 14 rectangular grid, so the total number of locations is 270. Also, the percentages of organic matter in a soil sample are collected. The data was studied by Christensen and Waagepetersen (2002) to investigate whether weed occurrence could be predicted from observations of soil texture and soil chemical properties.

Usage

data(Weed95)

Format

A data frame with 270 observations and 6 variables.

xloc

Cartesian x-coordinate of the locations (in meter).

yloc

Cartesian y-coordinate of the locations (in meter).

weedcount

Number of weed collected at the given site.

scaled Y coord

The scaled Y coordinate with range -1 to 1 as a covariate in regression.

organic

Another chemical component indicating the organic matter of the soil.

dummy

A dummy variable taking values 0 or 1. If 0 it is treated as observed location and 1 treated as predicted location in Christensen and Waagepetersen (2002).

References

Christensen,O. and Waagepetersen,R. (2002) Bayesian Prediction of Spatial Count Data Using Generalized Linear Mixed Models. Biometrics, 58:280-286

Examples

data(Weed95)
str(Weed95)