Description Usage Arguments Details Value Author(s) References See Also Examples

Phisically exclude the collinear variables which are identified using `vifcor`

or `vifstep`

from a set of variables.

1 |

`x` |
explanatory variables (predictors), defined as a raster object ( |

`vif` |
an object of class |

`...` |
additional argument as in |

Before using this function, you should execute one of `vifstep`

or `vifcor`

which detect collinearity based on calculating variance inflation factor (VIF) statistics. If `vif`

is missing, then `vifstep`

is called.

an object of class same as `x`

(i.e. `RasterStack`

or `RasterBrick`

or `data.frame`

or `matrix`

)

Babak Naimi [email protected]

IF you used this method, please cite the following article for which this package is developed:

Naimi, B., Hamm, N.A.S., Groen, T.A., Skidmore, A.K., and Toxopeus, A.G. 2014. Where is positional uncertainty a problem for species distribution modelling?, Ecography 37 (2): 191-203.

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 | ```
## Not run:
file <- system.file("external/spain.grd", package="usdm")
r <- brick(file) # reading a RasterBrick object including 10 raster layers in Spain
r
vif(r) # calculates vif for the variables in r
v1 <- vifcor(r, th=0.9) # identify collinear variables that should be excluded
v1
re1 <- exclude(r,v1) # exclude the collinear variables that were identified in
# the previous step
re1
v2 <- vifstep(r, th=10) # identify collinear variables that should be excluded
v2
re2 <- exclude(r, v2) # exclude the collinear variables that were identified in
# the previous step
re2
re3 <- exclude(r) # first, vifstep is called
re3
## End(Not run)
``` |

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