convnum {adehabitat} | R Documentation |
The objects of class kasc
may contain maps of type "numeric"
(e.g. the elevation) or of type "factor"
(e.g. the type of
vegetation). convnum
centres and scales the maps of type
"numeric"
, and factor maps are transformed into a collection of k
maps of type "numeric"
(where k is the number of levels of the
factor), with zero means and unit variance (see dudi.mix
in the
ade4
package for further details).
convnum(kasc)
kasc |
an object of class kasc |
Returns a list with the following components:
kasc |
an object of class kasc |
weight |
the weights associated with each map of the object kasc, so that the collection of maps defining a categorical variable has the same weight that a numeric variable (see examples). |
Clément Calenge calenge@biomserv.univ-lyon1.fr
## loads the data data(puechabon) kasc <- puechabon$kasc image(kasc) ## scales all the variables toto <- convnum(kasc) image(toto$kasc) ## the Aspect has four levels: ## four variables have been defined. toto$weight ## The sum of the weights given to each ## level of aspect is equal to: toto$weight[2:5] sum(toto$weight[2:5]) ## The same weight is therefore given to the factor variable Aspect and ## to any continuous variable, e.g. the elevation.