The function Don
measures the dynamic interaction between two moving objects following
the methods outlined by Doncaster (1990).
1  Don(traj1, traj2, tc = 0, dc = 50)

traj1 
an object of the class 
traj2 
same as 
tc 
time threshold for determining simultaneous fixes – see function: 
dc 
distance tolerance limit (in appropriate units) for defining when two fixes are spatially together. 
This function can be used to compute the Doncaster (1990) methods for measuring
dynamic interaction between two objects. The Doncaster method tests the proportion
of simultaneous fixes that are below dc
against that which would be
expected based on the distribution of distances between all fixes.
This function first returns a plot, for distance values ranging from 0 to the maximum
distance separating two fixes, of the observed proportion of simultaneous fixes below
each distance value. The expected values based on all fixes are also included.
Second, a list is returned that contains the contingency table of simultaneous fixes
(paired) and nonpaired fixes below and above dc
, along with the
associated pvalue from the Chisquared test.
conTable – contingency table showing frequency of paired and nonpaired fixes above and below dc
.
p.value – pvalue from the Chisquared test of conTable
.
Doncaster, C.P. (1992) Nonparametric estimates of interaction from radiotracking data. Journal of Theoretical Biology, 143: 431443.
GetSimultaneous
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