BiodiversityR: residualssurface – R documentation

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residualssurface

Show and Interpolate Two Dimensional Distribution of Residuals

Description

This function interpolates the spatial structure of residuals of a GLM through gam or surf.ls and optionally provides a graph.

Usage

residualssurface(model, data, x, y, gam = F, npol = 2, plotit = T, filled = F, bubble = F)

Arguments

`model`	Result of GLM as calculated by `glm` or `glm.nb`.
`data`	Data set that contains the spatial coordinates of the sample units used for the original model (specified as "x" and "y").
`x`	Horizontal position of the sample units.
`y`	Vertical position of the sample units.
`gam`	Interpolate the spatial structure by `gam` (if "TRUE") or by `surf.ls` (if "FALSE").
`npol`	Degree of polynomial surface as passed to `surf.ls`.
`plotit`	Plot the interpolated surface (through `interp` and the residuals) .
`filled`	Fill the contours by `filled.contour`.
`bubble`	Provide a bubble graph of the residuals: circles indicate positive residuals, whereas squares indicate negative residuals.

Details

The function reports the results of a GAM or least-squares trend surface analysis of the spatial distribution of residuals of a model (through residuals).

Optionally, a graph is produced that can contain the trend surface, filled contours and bubble graphs in addition to the spatial location of the sample units.

Value

The function reports the results of a GAM or least-squares trend surface analysis of the spatial distribution of residuals. Optionally, a graph is provided.

Author(s)

Roeland Kindt (World Agroforestry Centre)

References

Kindt, R. & Coe, R. (2005) Tree diversity analysis: A manual and software for common statistical methods for ecological and biodiversity studies.

https://www.worldagroforestry.org/output/tree-diversity-analysis

Examples

library(vegan)
library(mgcv)
library(akima)
data(faramea)
Count.model1 <- lm(Faramea.occidentalis ~ Precipitation,
    data=faramea, na.action=na.exclude)
surface.1 <- residualssurface(Count.model1, na.omit(faramea),
    'UTM.EW', 'UTM.NS', gam=TRUE, plotit=TRUE, bubble=TRUE)

BiodiversityR

Package for Community Ecology and Suitability Analysis

v2.13-1

GPL-3

Authors

Roeland Kindt [cre, aut] (<https://orcid.org/0000-0002-7672-0712>)

Initial release

2021-4-15