findlocal: Search for likely occurrences

Description Usage Arguments Examples

View source: R/search_fun.R

Description

This is a Markov Chain like search procedure to construct a set of likely occurrences for a given sample of known occurrences. Simulated occurrences are accepted if each one is more likely than the parent locality used to find the simulated point AND if the multivariate likelihood of the entire sample is improved. The improvement of the entire sample is calculated after each parent locality is visited once in the search process. The process is repeated a given number of times (think Markov Chain again), to hopefully reach a near optimal set of simulated occurrences.

Usage

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findlocal(ext_ob, clim, type = ".kde", maxiter = 50, searchrep = 3,
  manip = "condi", alpha = 0.05, factor = 4, n = 1024, w = FALSE)

Arguments

ext_ob

A data.frame of climate values (i.e., extracted from the climate raster object). Will be passed to multiv_likelihood().

clim

A raster object of climate data (matching x)

type

Designate either ".gauss" or ".kde".

maxiter

Maximum number of search iterations.

searchrep

How many times to search for simulated localities (per parent occurrence) per iteration. Recommend 1, but feel free to tune this parameter.

manip

Specify either 'reg', 'condi', or 'bayes. Default is 'condi'. See documentation for densform() for descriptions of these.

alpha

The value of alpha to be used to calculate the initial confidence interval for removing climatic outliers in the sample(s).

factor

To be passed to the extraction() function for post search thinning of data to limit overfitting. Set to 1 to ignore.

n

An integer value of the number of bins to use for Kernel Density Estimation

w

To weight the log-likelihoods by coefficient of variation or not.

Examples

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## Not run: 

data(abies);
ext.abies = extraction(abies, climondbioclim, schema='flat', factor =4);
sea <- findlocal(
 ext.abies, climondbioclim, 
 type = '.kde', 
 maxiter = 15, searchrep = 1, 
 manip = 'condi');
 plot_clim(sea[[1]], climondbioclim[[5]])
 
## End(Not run)

rsh249/vegdistmod documentation built on May 28, 2019, 3:31 a.m.