SI.micro {RGeostats}R Documentation

Microstructure index

Description

The microstructure index measures the relative importance of structural components that have a smaller scale than the sampling lag (including random noise).

Usage

SI.micro(db, h0, pol, dlim, ndisc)

Arguments

db

Name of the db-class which contains the data

h0

Mean lag between samples.

pol

The polygon-class which contains the series of Polysets.

dlim

The limit distance for valuating a node, when migrating points on a grid for computing the covariogram. GiVEN IN THE PROJECTED SPACE UNITS.

ndisc

Discretization of the data area when constructing the defaulted grid.

Value

The microstructure index.

Note

Function originally developped for the EU project Fisboat, DG-Fish, STREP no 502572. Authors: Woillez, M., and Rivoirard, J. (Geosciences/Mines-ParisTech)

Author(s)

Mathieu Woillez, Ifremer, 2013

References

Woillez, M., Poulard, J-C., Rivoirard, J., Petitgas, P., and Bez, N. 2007. Indices for capturing spatial patterns and their evolution in time, with application to European hake (Merluccius merluccius) in the Bay of Biscay. - ICES Journal of Marine Science, 64: 537-550. http://icesjms.oxfordjournals.org/content/64/3/537.abstract

Woillez, M., Rivoirard, J., and Petitgas, P. 2009. Notes on survey-based spatial indicators for monitoring fish populations. - Aquatic Living Resources, 22: 155-164. http://journals.cambridge.org/action/displayAbstract?fromPage=online&aid=8215490

Examples

# Load data
rg.load(filename="Demo.hake.bob.db.data",objname="db.data")
rg.load(filename="Demo.hake.bob.poly.data",objname="poly.data")
projec.define(projection="mean",db=db.data)

mic = SI.micro(db.data,h0=10,pol=poly.data,dlim=50,ndisc=400)
cat("Microstructure Index = ",mic,"\n")

rm(db.data,poly.data)

[Package RGeostats version 11.0.6 Index]