gavinsimpson/gratia


ggplot-based graphics and useful functions for GAMs fitted using the mgcv package

https://gavinsimpson.github.io/gratia/

License: Other

Language: R

Keywords: generalized-additive-models, ggplot2, r-package


gratia

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Overview

Graceful 'ggplot'-based graphics and utility functions for working with generalized additive models (GAMs) fitted using the 'mgcv' package. Provides a reimplementation of the plot() method for GAMs that 'mgcv' provides, as well as 'tidyverse' compatible representations of estimated smooths.

Features

The main features of gratia are currently

  • A ggplot2-based replacement for mgcv:::plot.gam(): draw(gam_model).

    Estimated smooths from a GAM

    Note specialist smoothers (bs %in% c("sos","mrf","so")) are not currently supported, but univariate, factor and continuous by-variable smooths, simple random effect smooths (bs = 're'), factor-smooth interaction smooths (bs = "fs"), and bivariate tensor product smooths are supported,

  • Estimatation of derivatives of fitted smoothers: derivatives() (older functionality in fderiv(gam_model)),

  • Estimation of point-wise across-the-function confidence intervals and simultaneous intervals for smooths: confint(gam_model).

  • Model diagnostics via appraise()

    Model diagnostics figure

Installing gratia

gratia is now available on CRAN, and can be installed with

install.packages('gratia')

however gratia is under active development and you may wish to install the development version from github. The easiest way to do this is via the install_github() function from package remotes. Make sure you have remotes installed, then run

remotes::install_github("gavinsimpson/gratia")

to install the package.

History

gratia grew out of an earlier package, schoenberg, itself a development of the earlier package tsgam, which was originally intended to be used with GAMs fitted to time series. As I was developing tsgam however it became clear that the package could be used more generally and that the name "tsgam" was no longer appropriate. To avoid breaking blog posts I had written using tsgam I decided to copy the git repo and all the history to a new repo for the package under the name schoenberg. At a later date someone released another package called schoenberg to CRAN, so that scuppered that idea. Now I'm calling the package gratia. Hopefully I won't have to change it again…

Why gratia?

In naming his greta package, Nick Golding observed the recent phenomena of naming statistical modelling software, such as Stan or Edward, after individuals that played a prominent role in the development of the field. This lead Nick to name his Tensor Flow-based package greta after Grete Hermann.

In the same spirit, gratia is named in recognition of the contributions of Grace Wahba, who did pioneering work on the penalised spline models that are at the foundation of the way GAMs are estimated in mgcv. I wanted to name the package grace, to explicitly recognise Grace's contributions, but unfortunately there was already a package named Grace on CRAN. So I looked elsewhere for inspiration.

The English word "grace" derives from the Latin gratia, meaning "favor, charm, thanks" (according to Merriam Webster).

The chair that Grace Wabha currently holds is named after Isaac J Schoenberg, a former University Madison-Wisconsin Professor of Mathematics, who in a 1946 paper provided the first mathematical reference to "splines". (Hence the previous name for the package.)

Project Statistics

Sourcerank 7
Repository Size 10.4 MB
Stars 66
Forks 10
Watchers 4
Open issues 24
Dependencies 19
Contributors 2
Tags 2
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Gavin Simpson singmann

Packages Referencing this Repo

gratia
Graceful 'ggplot'-Based Graphics and Other Functions for GAMs Fitted Using 'mgcv'
Latest release 0.2-8 - Updated - 66 stars

Recent Tags See all

v0.2-3 February 11, 2019
v0.2-0 January 17, 2019

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