Weed95 {gcKrig} | R Documentation |
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)