Movement Correlation Coefficient

Description

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

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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.

See Also

GetSimultaneous, DI

Examples

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data(deer)
deer37 <- deer[1]
deer38 <- deer[2]
#tc = 7.5 minutes
Cr(deer37, deer38, tc = 7.5*60)