get.datasets

a list of character vectors of model names 
with the elements named by species code

model.names

a list of the ddf models named in model.names

ddf.models

Compiles a list of unique model combinations, which are stored as character 
vectors within the list. The associated data for the models in each of the
elements of this list are also obtained (these will only be one per set
of models as each model group must use the same data). It also constructs a 
look up table in the from of a named character vector to relate species code
to models as these have now been reduced to unique model combinations only.

internal

Performs distance sampling analyses on a number of species
at once and can account for unidentified sightings, model uncertainty
and covariate uncertainty. Unidentified sightings refer to sightings
which cannot be allocated to a single species but may instead be
allocated to a group of species. The abundance of each unidentified
group is estimated and then prorated to the species estimates. Model
uncertainty should be incorporated when multiple models give equally
good fit to the data but lead to large differences in estimated
density / abundance. Covariate uncertainty should be incorporated
when covariates cannot be measured accurately, for example this is
often the case for group size in marine mammal surveys. Variance
estimation for these methods is via a non parametric bootstrap.
The methods implemented are described in Gerodette T. and Forcada
J. (2005) <doi:10.3354/meps291001> Non-recovery of two spotted and
spinner dolphin populations in the eastern tropical Pacific Ocean.

get.datasets: Extracts the data and models from the ddf objects

Description

Usage

Arguments

Value