Introduction

This package was put together to give the CU Boulder Office of Data Analytics a resource to help us keep our plots uniform in presentation and consistent with the CU Boulder brand specifications. It operates as a GGPlot theme, and can be installed directly from this repo. Usage is fairly simple, and is detailed below.

Installation

To install this package run the following in either RStudio or your R console:

install.packages('devtools') # ignore if devtools already installed
devtools::install_github('cu-boulder/themeODA')

Colors

The color palette implemented here includes three shades of gray (dark gray, medium gray, and light gray), taken directly from the CU Boulder web style guide, as well as a six color palette (gold, black, blue, green, red, and purple):

While the first three colors are taken directly from the guide, some adjustments were necessary for green, red, and purple. The green and red colors chosen by the style guide are not visually distinct from the blue and black used here, and purple is not included in the guide at all. Consistent with the style guide recommendations, these new colors were instead selected from the Material Design palette to maximize visual contrast with gold, black, and blue.

The priority of each color in the palette is indicated by their left-right ordering in the above palette image. While single-color plots will default to black (following ggplot defaults) gold isthe primary color for two-color plots, along with black as the secondary. The later colors, blue, green, etc. are only used as additional colors are required. In general, red and purple should be considered "low-priority", as both are difficult to distinguish from blue and green for people with colorblindness. If five or more colors are needed, it is reconmmended to consider using shape or other visual channels to improve plot legibility.

Usage

The package has two components, a base theme (theme_oda()) and a set of scale functions (scale_color_ and scale_fill_) to apply the color palette. These are illustrated below using the penguins` example dataset.

library(ggplot2)
library(themeODA)
library(magrittr)
library(palmerpenguins)

# a simple scatterplot using the first two colors in the scale
scatter = ggplot(penguins,aes(x=bill_length_mm, y=bill_depth_mm, color=sex)) +
                 geom_point() +
                 # the base font size can be specified (base_size) as well as the presence of a legend
                 theme_oda(base_size=16, legend=TRUE) + 
                 scale_color_oda() +
                 labs(x='Bill Length (mm)', y='Bill Depth (mm)', title = 'Penguin Beak Dimensions',color='Sex')

scatter

# themeODA also provides a gradient color scale, which defaults to black-gold
scatter.gradient = ggplot(penguins,aes(x=bill_length_mm, y=flipper_length_mm, color=body_mass_g)) +
    geom_point() + 
    theme_oda(base_size=16) +
    scale_color_oda_gradient() +
    labs(x='Bill Length (mm)',y='Flipper Length (mm)',title='Penguin Proportions', color='Body Mass (g)')

scatter.gradient

# if additional visual contrast is required an intermediate color and be used
scatter.gradient = ggplot(penguins,aes(x=bill_length_mm, y=flipper_length_mm, color=body_mass_g)) +
    geom_point() + 
    theme_oda(base_size=16) +
    scale_color_oda_gradient(mid='blue') +
    labs(x='Bill Length (mm)',y='Flipper Length (mm)',title='Penguin Proportions', color='Body Mass (g)')

scatter.gradient

# the scale_fill family provides functionality for histograms and bar charts
histogram = ggplot(penguins,aes(x=body_mass_g,group=species, fill=species)) + 
    geom_histogram() +
    theme_oda(base_size=16) +
    scale_fill_oda() +
    labs(x='Body Mass (g)', y='', title='Body Mass by Species', fill='Species')

histogram

penguins$species.island = as.factor(paste0(penguins$species,'+\n',penguins$island))

bar = ggplot(penguins,aes(x=species.island,fill=species.island)) +
    geom_bar() +
    theme_oda(base_size=16, legend=FALSE) +
    scale_fill_oda() +
    labs(y='',x='Species+Island',title='Records per Species and Island',fill='Species+Island')

bar