I am unable to specify error spatial autocorrelation structure in glmmPQL: DATA x and y coordinates for sample points at which presence/absence of seedlings and canopy openness were recorded in different forest stands.
QUESTION Does seedling density increase with canopy openness? ANALYSIS Initial analysis using glmmPQL with binomial errors and stand as random effect > result <- glmmPQL(seedlings ~ canopy, random = ~1|stand, family=binomial, data=regen) Semivariogram of residuals from this fit using geoR showed spatial autocorrelation with range 34.9 m and relative nugget of 75%. Therefore I tried to create a corStruct object: > corel <- corSpher(value = c(34.9,0.75), form = ~x+y, nugget=TRUE) > corel <- Initialize(corel, data = regen) And specify the structure in a new glmmPQL > result2 <- glmmPQL(seedlings ~ canopy, random = ~|stand, family = binomial, correlation = corel, data=regen) PROBLEM I get the error message: iteration 1 Error in eval(expr, envir, enclos) : Object "x" not found (Running R 1.9.1 on Windows ME) I appear to be implementing corSpher and Initialize incorrectly- any help greatly appreciated. ____________________________ Dr. Daniel P. Bebber Department of Plant Sciences University of Oxford South Parks Road Oxford OX1 3RB Tel. 01865 275060 --- ______________________________________________ [EMAIL PROTECTED] mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide! http://www.R-project.org/posting-guide.html