convert.polar {MDSMap}

Convert Cartesian coordinates from wMDS coordinates to polar coordinates.

Description

Converts the coordinates of points in the final configuration of a spherically constrained wMDS from Cartesian to polar coordinates.

Usage

convert.polar(mdsobject, nloci)

Arguments

mdsobject

Output from smacofSphere using the dual method in the smacof package.

nloci

The number of markers in the configuration.

Details

Centres the circle on zero if necessary, finds a the most natural break in the points to start as 0, then calculates the angle of each point relative to this. The radius is the median distance of points from the centre.

Value

theta

A vector of angles one for each point.

radius

A scalar the radius of sphere.

References

de Leeuw J, Mair P (2009) Multidimensional scaling using majorization: SMACOF in R. J Stat Softw 31:1-30 http://www.jstatsoft.org/v31/i03/

See Also

smacofSphere

Examples

#M and lod should be n x n symmetric matrices of the same dimensions where n 
#is the number markers to be analysed
## Not run: 
mds1<-smacofSphere(M,ndim=2,algorithm="dual",weightmat=lod,penalty=100)
pol<-convert.polar(mds1,n)

## End(Not run)