https://github.com/JoGall/terminator

R port of the Leaflet.Terminator.js plugin to show day / night regions on a map
https://github.com/JoGall/terminator

Last synced: 3 months ago
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R port of the Leaflet.Terminator.js plugin to show day / night regions on a map

• Host: GitHub
• URL: https://github.com/JoGall/terminator
• Owner: JoGall
• Created: 2018-01-25T12:35:07.000Z (almost 7 years ago)
• Default Branch: master
• Last Pushed: 2018-01-25T13:02:39.000Z (almost 7 years ago)
• Last Synced: 2024-05-21T02:53:28.013Z (6 months ago)
• Language: R
• Homepage:
• Size: 4.88 KB
• Stars: 7
• Watchers: 2
• Forks: 0
• Open Issues: 1
• Metadata Files:
  • Readme: README.md

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README

        
# terminator

This is a simple R port of the [Leaflet](https://rstudio.github.io/leaflet/morefeatures.html) plugin [Leaflet.Terminator.js](https://github.com/joergdietrich/Leaflet.Terminator/blob/master/L.Terminator.js) intended to indicate day and night regions on a map.

Although this function worked for `leaflet` maps, I made this function in order to visualise terminators on `ggplot` maps, such as animations like this:

![terminator-animation](https://user-images.githubusercontent.com/17113779/35389041-096c2786-01ce-11e8-98b6-cfa915f8e989.gif)

Produced like so:

```{r}

library(dplyr)

library(ggplot2)

library(ggthemes)

library(gganimate)

library(animation)

terminatorLatLon <- lapply(seq(0, 23, 1), function(x) {

  

  t0 <- as.POSIXct(Sys.Date()) + (60*60*x)

  

  terminator(t0, -180, 190, 0.5) %>%

    mutate(frame = x)

}) %>%

  plyr::rbind.fill()

chart <- ggplot(terminatorLatLon, aes(frame = frame)) +

  borders("world", colour = "gray90", fill = "gray85") +

  geom_ribbon(aes(lat, ymax = lon), ymin = 90, alpha = 0.2) +

  coord_equal(xlim = c(-180, 190), ylim = c(-58, 85), expand = 0) +

  theme_map()

gganimate(chart, interval = 0.1, ani.width=1000, ani.height=600, filename = "terminator-animation.gif")

```