logObsInd

observations/visits for the focal species

focal

observations/visits for the reference species group

group

if TRUE, assumes that the observations for the focal species are
included in 'group' and will remove them

fs.rm

if TRUE, the result is normalized to a 0-1 range

norm

This function implements the algorithms to calculate the observation index.
OI = log ( (At / (At + Rt) ) / ( A / (A + R) ) )
where At is the sum of observations for focal species during time t (or grid),
Rt is sum of observations of all species in reference group during t,
A and R are the total sums for observations.

internal

It helps making the evaluation and preparation of biodiversity data
easy, systematic and reproducible. It also helps the users to overlay the
point observations into a custom grid that is useful for further analysis.
The review summarise statistics that helps evaluate whether a set of species
observations is fit-for-use and take decisions upon its use of on further
analyses. It does so by quantifying the sampling effort (amount of effort
expended during an event) and data completeness (data gaps) to help judge
whether the data is representative, valid and fit for any intended purpose.
The 'BIRDS' package is most useful when working with heterogeneous data sets
with variation in the sampling process, i.e. where data have been collected
and reported in various ways and therefore varying in sampling effort
and data completeness (i.e. how well the reported observations describe the
true state). Primary biodiversity data (PBD) combining data from different
data sets, like e.g. Global Biodiversity Information Facility (GBIF) mediated
data, commonly vary in the ways data has been generated - containing
opportunistically collected presence-only data together with and data from
systematic monitoring programs. The set of tools provided is aimed at
understanding the process that generated the data (i.e. observing, recording
and reporting species into databases). References:
Ruete (2015) <doi:10.3897/BDJ.3.e5361>; Szabo, Vesk, Baxter & Possingham (2010)
<doi:10.1890/09-0877.1>; Telfer, Preston 6 Rothery (2002) <doi:10.1016/S0006-3207(02)00050-2>.

logObsInd: The actual observation index function

Description

Usage

Arguments

Value

References