Rbar2kappa {geostats} | R Documentation |
to
conversion
Description
Converts the empirical concentration parameter
to the von-Mises concentration parameter
.
Usage
Rbar2kappa(R, p = 1)
Arguments
R |
a scalar or vector of values between 0 and 1 |
p |
the number of parameters |
Details
and
are two types of
concentration parameter that are commonly used in directional
data analysis.
is one of the parameters of the
parametric von Mises distribution, which is difficult to
estimate from the data.
is easier to calculate
from data.
Rbar2kappa
converts to
using the following approximate empirical
formula:
where marks the number of parameters in the data space (1
for circle, 2 for a sphere).
Value
value(s) between 0 and
References
Banerjee, A., et al. “Clustering on the unit hypersphere using von Mises-Fisher distributions.” Journal of Machine Learning Research 6.Sep (2005): 1345-1382.
Examples
data(striations,package='geostats')
Rbar2kappa(Rbar(striations,degrees=TRUE))