dbar is the mean distance between consecutive capture locations,
pooled over individuals (e.g. Efford 2004).
RPSV (for 'Root Pooled Spatial Variance') is a measure of the 2-D
dispersion of the locations at which individual animals are detected,
pooled over individuals.
MMDM (for 'Mean Maximum Distance Moved') is the average maximum
distance between detections of each individual i.e. the observed range
length averaged over individuals (Otis et al. 1978).
ARL or 'Asymptotic Range Length') is obtained by fitting an
exponential curve to the scatter of observed individual range length vs
the number of detections of each individual (Jett and Nichols 1987: 889).dbar(capthist)
RPSV(capthist)
MMDM(capthist, min.recapt = 1, full = FALSE)
ARL(capthist, min.recapt = 1, plt = FALSE, full = FALSE)capthistcapthist
is a multi-session list.
The full argument may be used with MMDM and ARL to
return more extensive output, particularly the observed range length for
each detection history.dbar is defined as
$$\overline{d}=\frac{\sum\limits _{i=1}^{n}
\sum\limits _{j=1}^{n_i - 1}
\sqrt{(x_{i,j}-x_{i,j+1})^2 + (y_{i,j}-y_{i,j+1})^2}}
{\sum\limits _{i=1}^{n} (n_i-1)}$$
RPSV is defined as
$$RPSV = \sqrt{
\frac {\sum\limits _{i=1}^{n} \sum\limits _{j=1}^{n_i} [
(x_{i,j} - \overline x_i)^2 + (y_{i,j} - \overline y_i)^2
]}{\sum\limits _{i=1}^{n} (n_i-1) - 1}}$$
dbar and RPSV have a specific role as proxies for
detection scale in inverse-prediction estimation of density (Efford
2004; see ip.secr).
RPSV is used in autoini to obtain plausible starting
values for maximum likelihood estimation.
MMDM and ARL discard data from detection histories
containing fewer than min.recapt+1 detections.autoinidata(secrdemo)
dbar(captdata)
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