Mark-Recapture Distance Sampling (MRDS) Analysis of Trial Observer Configuration and Point Independence
1 2 3 |
dsmodel |
distance sampling model specification; model list with key function and scale formula if any |
mrmodel |
mark-recapture model specfication; model list with formula and link |
data |
analysis |
meta.data |
list containing settings controlling data structure |
control |
list containing settings controlling model fitting |
call |
original function call used to call |
MRDS analysis based on point independence involves two separate and
independent analyses of the mark-recapture data and the distance sampling
data. For the trial configuration, the mark-recapture data are analysed
with a call to ddf.trial.fi
(see likelihood eq 6.12 and 6.17
in Laake and Borchers 2004) to fit a conditional distance sampling detection
function for observer 1 based on trials (observations) from observer 2 to
estimate p_1(0), detection probability at distance zero for observer 1.
Independently, the distance data from observer 1 are used to fit a
conventional distance sampling (CDS) (likelihood eq 6.6) or multi-covariate
distance sampling (MCDS) (likelihood eq 6.14) model for the detection
function, g(y), such that g(0)=1. The detection function for observer 1 is
then created as p_1(y)=p_1(0)*g(y) (eq 6.28 of Laake and Borchers 2004) from
which predictions are made. ddf.trial
is not called directly by the
user and is called from ddf
with method="trial"
.
For a complete description of each of the calling arguments, see
ddf
. The argument dataname
is the name of the
dataframe specified by the argument data
in ddf
. The arguments
dsmodel
, mrmodel
, control
and meta.data
are
defined the same as in ddf
.
result: a trial model object which is composed of trial.fi
and ds
model objects
Jeff Laake
Laake, J.L. and D.L. Borchers. 2004. Methods for incomplete detection at distance zero. In: Advanced Distance Sampling, eds. S.T. Buckland, D.R.Anderson, K.P. Burnham, J.L. Laake, D.L. Borchers, and L. Thomas. Oxford University Press.
ddf.trial.fi
, ddf.ds
, summary.trial
, coef.trial
, plot.trial
, gof.trial
Questions? Problems? Suggestions? Tweet to @rdrrHQ or email at ian@mutexlabs.com.
All documentation is copyright its authors; we didn't write any of that.