ecospat (version 3.3)

ecospat.adj.D2.glm: Calculate An Adjusted D2

Description

This function is used for calculating an adjusted D2 from a calibrated GLM object

Usage

ecospat.adj.D2.glm(glm.obj)

Value

Returns an adjusted D square value (proportion of deviance accounted for by the model).

Arguments

glm.obj

Any calibrated GLM object with a binomial error distribution

Author

Christophe Randin and Antoine Guisan

Details

This function takes a calibrated GLM object with a binomial error distribution and returns an evaluation of the model fit. The measure of the fit of the models is expressed as the percentage of explained deviance adjusted by the number of degrees of freedom used (similar to the adjusted-R2 in the case of Least-Square regression; see Weisberg 1980) and is called the adjusted-D2 (see guisan and Zimmermann 2000 for details on its calculation).

References

Weisberg, S. 1980. Applied linear regression. Wiley.

Guisan, A., S.B. Weiss and A.D. Weiss. 1999. GLM versus CCA spatial modeling of plant species distribution. Plant Ecology, 143, 107-122.

Guisan, A. and N.E. Zimmermann. 2000. Predictive habitat distribution models in ecology. Ecol. Model., 135, 147-186.

Examples

data(ecospat.testData)
glm.obj<-glm(Achillea_millefolium~ddeg+mind+srad+slp+topo, 
family = binomial, data=ecospat.testData)

ecospat.adj.D2.glm(glm.obj)