calculate.dht

species.name

character vector giving the field name of the 
ddf data that contains the species codes

species.field.name

named character vector which acts as a look up table for
duplicate detection function models

model.index

ddf.results

dataframe of region records - Region.Label and Area

region.table

dataframe of sample records - Region.Label,
Sample.Label, Effort

sample.table

dataframe of observation records with fields object,
Region.Label, and Sample.Label which give links to sample.table,
region.table and the data records used in <code>model</code>

obs.table

a list of the options to be supplied to mrds::dht

dht.options

Calculates the abundance for each species code including the unidentified 
codes if supplied.

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.

calculate.dht: Calculates the abundance for each species code including the unidentified codes if supplied.

Description

Usage

Arguments

Value

See Also