intamap (version 1.3-21)

rotateAnisotropicData: rotateAnisotropicData

Description

This function applies an isotropic transformation of the coordinates specified in object.

Usage

rotateAnisotropicData(object,anisPar)

Arguments

object

(i) An Intamap type object (see intamap-package) containing one SpatialPointsDataFrame data frame named

anisPar

An array containing the anisotropy parameters (anisotropy ratio and axes orientation) (see estimateAnisotropy) for the rotation. If object is the output of

Value

• (i) A modified object with transformed coordinates if rotateAnisotropicData is called with an Intamap object as input (see intamap-package) or (ii) the transformed coordinates if a SpatialPointsDataFrame is used as input or (iii) the transformed coordinates if a SpatialPoints object is the input.

Details

This function performs a rotation and rescaling of the coordinate axes in order to obtain a new coordinate system, in which the observations become statistically isotropic. This assumes that the estimates of the anisotropy ratio and the orientation angle provided in anisPar are accurate.

References

[1] http://www.intamap.org

[2] A. Chorti and D. T. Hristopulos (2008). Non-parametric Identification of Anisotropic (Elliptic) Correlations in Spatially Distributed Data Sets, IEEE Transactions on Signal Processing, 56(10), 4738-4751 (2008).

See Also

estimateAnisotropy

Examples

library(gstat)
    data(sic2004)
    coordinates(sic.val)=~x+y
    sic.val$value=sic.val$dayx

    anisPar <- estimateAnisotropy(sic.val)
    print(anisPar)  

    rotatedObs <- rotateAnisotropicData(sic.val,anisPar)

    newAnisPar <- estimateAnisotropy(rotatedObs)
    print(newAnisPar)