https://github.com/hrbrmstr/terminator
Rcpp implementation of day/night terminator generator
https://github.com/hrbrmstr/terminator
daynight geospatial r rcpp rstats terminator
Last synced: 4 months ago
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Rcpp implementation of day/night terminator generator
- Host: GitHub
- URL: https://github.com/hrbrmstr/terminator
- Owner: hrbrmstr
- Created: 2018-01-25T22:40:15.000Z (over 7 years ago)
- Default Branch: master
- Last Pushed: 2018-01-26T03:47:01.000Z (over 7 years ago)
- Last Synced: 2024-02-03T11:04:03.066Z (over 1 year ago)
- Topics: daynight, geospatial, r, rcpp, rstats, terminator
- Language: C++
- Size: 3.43 MB
- Stars: 12
- Watchers: 4
- Forks: 1
- Open Issues: 1
-
Metadata Files:
- Readme: README.Rmd
Awesome Lists containing this project
README
---
output: rmarkdown::github_document
editor_options:
chunk_output_type: console
---
# terminator
Compute Global Terminator (Day/Night) Bands
## Description
Compute global terminator (day/night) bands which can be overlayed as day and night regions on a ggplot2 world map.
This is an Rcpp port of a [pure R port](https://github.com/JoGall/terminator) (by @JoGall) of a JS leaflet plugin.
## What's Inside The Tin
The following functions are implemented:
- `terminator`: Compute a single termiantor band
- `terminator_lat_lon`: Generate a full set of terminator frames
## Installation
```{r eval=FALSE}
devtools::install_github("hrbrmstr/terminator")
```
```{r message=FALSE, warning=FALSE, error=FALSE, include=FALSE}
options(width=120)
```
## Usage
(NOTE: If you're trying to just knit this Rmd, remove the `eval=FALSE` bits. I didn't want to keep generating things and was too impatient to wait for a `cache=TRUE` run).
```{r message=FALSE, warning=FALSE, error=FALSE}
library(terminator)
library(ggplot2)
library(gganimate) # devtools::install_github("dgrtwo/gganimate")
# current verison
packageVersion("terminator")
```
Joe had an asesome idea and made a perfectly fine pure R port. This one is just a wee bit faster.
```{r bench, eval=FALSE}
microbenchmark::microbenchmark(
pure_r = pure_r_terminator(as.POSIXct(Sys.Date()) + (60*60*0), -180, 190, 0.5),
rcpp = terminator::terminator(as.POSIXct(Sys.Date()) + (60*60*0), -180, 190, 0.5),
times=100
) -> mb
mb
## Unit: microseconds
## expr min lq mean median uq max neval
## pure_r 142373.445 157488.8415 174413.4417 173927.7860 184725.916 272773.959 100
## rcpp 483.505 553.2455 641.8395 609.8245 692.899 2487.993 100
```
Rather than use the built-in map data, we'll use an `rnaturalearth` so we don't need to mess with extended longitudes.
```{r wintri, fig.width=10}
library(ggalt)
library(rnaturalearth) # ropensci/rnaturalearth
world_map <- fortify(countries110)
ggplot() +
geom_cartogram(
data=world_map, map=world_map, aes(x=long, y=lat, map_id=id),
fill=NA, color="#2b2b2b"
) -> gg
for (i in 0:23) {
gg <- gg + geom_line(
data=terminator(as.integer((as.POSIXct(Sys.Date()) + (60*60*i))), -180, 180, 0.1),
aes(lon, lat), color="blue"
)
}
gg + coord_proj("+proj=wintri") + ggthemes::theme_map()
```
Animation with `magick`:
```{r magick, eval=FALSE}
library(magick)
library(rnaturalearth) # ropensci/rnaturalearth
library(tidyverse)
world_map <- fortify(countries110, region="name")
world_map <- filter(world_map, id != "Antarctica")
x <- image_graph(width=1000*2, height=500*2, res=144)
pb <- progress_estimated(24)
for (i in 0:23) {
pb$tick()$print()
ggplot() +
geom_cartogram(
data=world_map, map=world_map, aes(x=long, y=lat, map_id=id),
fill=NA, color="#2b2b2b", size=0.125
) +
geom_ribbon(
data=terminator(as.integer((as.POSIXct(Sys.Date()) + (60*60*(i)))), -180, 180, 0.1),
aes(lon, ymin=lat, ymax=90), fill="lightslategray", alpha=1/2
) +
scale_x_continuous(limits=c(-180, 180)) +
coord_quickmap() +
ggthemes::theme_map() -> gg
print(gg)
}
dev.off()
x <- image_animate(x)
image_write(x, "magick-preview.gif")
```
Using Joe's animation example:
```{r anim, eval=FALSE}
term_seq <- terminator_lat_lon()
chart <- ggplot(term_seq, aes(frame = frame)) +
borders("world", colour = "gray90", fill = "gray85") +
geom_ribbon(aes(lon, ymax = lat), ymin = 90, alpha = 0.2) +
coord_equal(xlim = c(-180, 190), ylim = c(-58, 85), expand = 0) +
ggthemes::theme_map()
gganimate(
chart,
interval = 0.1, ani.width=1000, ani.height=600,
filename = "terminator-animation.gif"
)
```
