animated_flights.Rmd

---
title: "Air Traffic Challenge"
output: 
  prettydoc::html_pretty:
    theme: cayman
    highlight: github
    toc: true 
    number_sections: true 
    df_print: paged
---

## Packages
```{r}
library(tidyverse) # dev ggplot version required: devtools::install_github("hadley/ggplot2")
library(sf)
library(readxl)
library(httr)
library(ggmap)
library(gganimate) # devtools::install_github("dgrtwo/gganimate")
library(hrbrthemes) # devtools::install_github("hrbrmstr/hrbrthemes")

```

# Create Geogif for one day of flights
```{r}

if (!require("pacman")) install.packages("pacman")

pacman::p_load(dplyr,sf,lwgeom,ggplot2,maps,maptools,rgeos)

#read in flight data
flight_sf <- readRDS("flight_sf.RDS")

flight_sf <- readRDS("twist_zrh_cleaned.RDS")
#filter flights for a single date
vizdata <- flight_sf %>% filter(date=="2017-01-01")

#create a new geometry : lines connecting Zurich Airport and the destination/origin of the flight
vizdata$flightline <- sf::st_union(vizdata$geometry, st_as_sfc("POINT(8 47)",crs=st_crs("+proj=longlat +datum=WGS84 +no_defs"))) %>% 
  st_cast("LINESTRING")

#get worldmap
world1 <- sf::st_as_sf(maps::map('world', plot = FALSE, fill = TRUE))

#plot on top (new ggplot2 2.3.0 version needed!)
ggplot(vizdata)+
  geom_sf(aes(geometry=flightline))+
  geom_sf(data=world1)

#we can now set the "flightline"-geometry as the main geometry in our dataset
st_geometry(vizdata) = "flightline"

#transform worldmap and flights into spheric projection
world2 <- sf::st_transform(
  world1,
  "+proj=laea +y_0=0 +lon_0=8 +lat_0=47 +ellps=WGS84 +no_defs"
)

flights2 <- sf::st_transform(
 vizdata,
 "+proj=laea +y_0=0 +lon_0=8 +lat_0=47 +ellps=WGS84 +no_defs"
)

#Plot!
ggplot() + 
  geom_sf(data=world2, color="white",size=0.2)+
  geom_sf(data=flights2, aes(color=as.numeric(diff_in_secs/60), size=as.numeric(diff_in_secs/60)),show.legend = "line")+
  theme_void()+
 scale_color_viridis_c(name="Delay (min)")+
  guides(alpha=F)+
  coord_sf(ndiscr=1000)+
  theme_ipsum()+
  guides(size=F)+
  theme(plot.background = element_rect(fill="#f5f5f2"))+
  transition_time(effective_time) +
  ease_aes('linear',interval = 0.2)+
  labs(title="A day of Flightmovements from / to ZRH",
       subtitle = 'Time : {frame_time}') 

# ?transition_time

anim_save("plot.gif")

```