emon-package: Tools for environmental and ecological survey design and...

Description Details Author(s) See Also


This package gives seven tools for designing and analysing ecological and environmental surveys. The tools are mainly designed for marine and benthic ecology applications, but they could easily be adopted for terrestrial ecology. Three of the tools give statistical power for specific survey designs (power.BACI, power.groups and power.trend). The fourth tool (precision) calculates the sample size needed to achieve specified precision for estimating the mean of some desired statistic together with the precision obtained for given n.

The other three tools are for more specialised applications. These are: the generalised visual fast count estimator for underwater video surveys (GVFCMOM); an estimate of the empirical semi-variogram for examining spatial correlation between stations (svariog); and detection probability for three spatial sampling designs (detect and detect.prop).


Package: emon
Type: Package
Version: 1.3.2
Date: 2017-03-03
License: GPL-3

The seven tools in this package are as follows:

Power for BACI designs (power.BACI, generate.trend, addnoise, mannkendall, mannkendall.stat, permute.BACI).

Power for comparing two groups (power.groups, permute.groups, size2.samevar).

Power for detecting trends (power.trend, generate.trend, addnoise).

Precision for estimating a mean (precision).

Sample sizes and probabilities for patch detection with different spatial sampling patterns (detect, detect.prop, fS.detect, fT.detect).

Semi-variogram function for investigating spatial dependency (svariog).

Method of moments estimator for Generalised Visual Fast Count estimation for video surveys (GVFCMOM, GVFC, expected.pois, expected.nb, mom.min.pois, mom.min.nb).

The help functions for the individual functions describe the methods used. However, perhaps the unique feature of the power functions in emon is that the statistical power is calculated by simulation. This has the disadvantage of increased computing time; however, the advantage is that the power calculations does not rely on the assumptions behind many of the theoretical results. The simulation method also means that power can be calculated for a range of data distributions and for a variety of statistical tests that might be used to evaluate p-values.


Jon Barry and David Maxwell

Maintainer: Jon Barry: Jon.Barry@cefas.co.uk

See Also

power.BACI, power.groups, power.trend, precision. detect, svariog, GVFCMOM

emon documentation built on May 2, 2019, 10:21 a.m.