Cr {wildlifeDI}

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

Cr(traj, traj2, tc = 0)

Arguments

traj

an object of the class move2 which contains the time-stamped movement fixes of at least two individuals. For more information on objects of this type see help(mt_as_move2).

traj2

(optional) same as traj, but for the second group of individuals. See checkTO

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. NOTE: This function is only appropriate with projected coordinates.

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

data(deer)
#tc = 7.5 minutes
Cr(deer, tc = 7.5*60)