# ggfan v0.1.0

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## Summarise a Distribution Through Coloured Intervals

Implements the functionality of the 'fanplot' package as 'geoms' for 'ggplot2'. Designed for summarising MCMC samples from a posterior distribution, where a visualisation is desired for several values of a continuous covariate. Increasing posterior intervals of the sampled quantity are mapped to a continuous colour scale.

# ggfan

Jason Hilton 14 November, 2017

## Summarise a distribution through coloured intervals

This package is a ggplot-based implementation of some of the functionality of the fanplot package by Guy Abel. Fanplot provides methods to visualise probability distributions by representing intervals of the distribution function with colours. Plotting samples from posterior distributions obtained through MCMC is a particular aim. A ggplot-based implementation is useful as it allows leverage of the power of ggplot2 features allowing, for example, facetting and easy theming.

## Installation

The package has recently been submitted to CRAN. Installation directly from CRAN will be possible if and when the package is accepted: install.packages("ggfan") Otherwise, the package can be installed directly from github using the devtools package: devtools::install_github("jasonhilton/ggfan").

## Quick Start

The provided fake_df data gives and example of the type of data you might want to plot with ggfan: it consists of 1000 samples of an outcome variable of interest at each value of a covariate x. We can plot this simply using standard ggplot2 syntax and geom_fan. Convenient ggplot features such as themes, colour scales and facetting can also be used.

ggplot(fake_df, aes(x=x, y=y)) + geom_fan() + theme_minimal() + scale_fill_distiller(palette="Spectral")


## Further Information

A full description of the functionality of ggfan is provided in the vignette, provided here.

A brief example of using ggfan to plot stan output is given in a second vignette here

## Functions in ggfan

 Name Description geom_fan Fan plot visualising intervals of a distribution gp_model_fit A stan_fit object used in the ggfan_stan vignette, containing posterior samples from a latent gaussian process model. This is provided as data to avoid having to conduct computationally expensive sampling when producing the vignettes. GeomIntervalPath See ggplot2-ggproto stat_interval Line plot visualising intervals of a distribution GeomIntervalPoly See ggplot2-ggproto stat_sample Plots a randomly chosen sample of the specified groups using geom_line StatInterval See ggplot2-ggproto StatIntervalFctr See ggplot2-ggproto StatSample See ggplot2-ggproto calc_quantiles Calculate quantiles of a tidy dataframe geom_interval Line plot visualising intervals of a distribution ggfan Fanplots for ggplot2 fake_df Fake dataset intended to resemble a set of MCMC samples of a variable over one covariate (perhaps time), No Results!