# ggperiodic

ggperiodic is an attempt to solve the issue of plotting periodic data in ggplot2. It automatically augments your data to wrap it around to any arbitrary domain.

## Installation

install.packages("ggperiodic")

Or you can install the development version from GitHub with:

# install.packages("devtools")
devtools::install_github("eliocamp/ggperiodic")

## Example

Let’s create some artificial data with periodic domain

x <- seq(0, 360 - 10, by = 10)*pi/180
y <- seq(-90, 90, by = 10)*pi/180

Z <- expand.grid(x = x, y = y)
Z\$z <- with(Z, 1.2*sin(x)*0.4*sin(y*2) -
0.5*cos(2*x)*0.5*sin(3*y) +
0.2*sin(4*x)*0.45*cos(2*x))

Z\$x <- Z\$x*180/pi
Z\$y <- Z\$y*180/pi

If you try to plot it, you’ll notice problems at the limits

library(ggplot2)
ggplot(Z, aes(x, y, z = z, color = ..level..)) +
geom_contour() +
coord_polar()
#> Warning: The dot-dot notation (`..level..`) was deprecated in ggplot2 3.4.0.
#> This warning is displayed once every 8 hours.
#> Call `lifecycle::last_lifecycle_warnings()` to see where this warning was
#> generated.

With ggperiodic you can define the periodic dimensions and ggplot2 does the rest.

library(ggperiodic)
#>
#> Attaching package: 'ggperiodic'
#> The following object is masked from 'package:stats':
#>
#>     filter
Z <- periodic(Z, x = c(0, 360))

ggplot(Z, aes(x, y, color = ..level..)) +
geom_contour(aes(z = z)) +
coord_polar()