The function Cr computes the correlation statistic for movement data as presented
in the paper by Shirabe (2006). The statistic is essentially a Pearson product-moment
correlation statistic formulated for use with movement data.
Usage
Cr(traj1, traj2, tc = 0)
Arguments
traj1
an object of the class ltraj which contains the time-stamped
movement fixes of the first object. Note this object must be a type II
ltraj object. For more information on objects of this type see
help(ltraj).
traj2
same as traj1.
tc
time threshold for determining simultaneous fixes – see function: GetSimultaneous.
Details
The function Cr can be used to measure the level of dynamic interaction (termed correlation)
between a pair of simultaneously moving objects. The statistic is sensitive to
interaction in both movement direction (azimuth) and displacement, but is unable to
disentangle the effects of these components.
Value
This function returns the Shirabe (2006) correlation statistic for two moving objects.
References
Shirabe, T. 2006. Correlation analysis of discrete motions. In: Raubal, M.,
Miller, HJ, Frank, AU, and Goodchild, M. eds. GIScience 2006, LNCS 4197. Berlin: Springer-Verlag;
370-382.