03_acc_armed_conflicts.Rmd

---
title: "Data access: Armed conflicts locations"
author: "Linda Petutschnig"
date: "25 5 2023"
output:
  html_document:
    theme: paper
    highlight: default
---

This script performs the following tasks:

- Accesses the ACLED database and retrieves entries within a user-defined space and time frame.
- Writes the result to hard drive.
 
```{r setup, include=FALSE}
knitr::opts_chunk$set(echo = TRUE)
```

```{r load, message = FALSE, warning = FALSE}

# Loads necessary packages
library(acled.api) # to access ACLED data
library(sf) # to manipulate vector features
library(here) # to access data via relative paths

# Contains the credentials necessary to access the ACLED data
source(here("00_acled_credentials.R")) 

# Add aceld.api
# https://www.rdocumentation.org/packages/acled.api/versions/1.1.5
# Citing ACLED: https://developer.acleddata.com/dashboard/terms-of-use/
 
```


```{r acled for aoi, message = FALSE, warning = FALSE}

# Reads the hexagon shapes 
aoi_shape <- st_read(here("data/geopackages", "AOI_hex5.gpkg"))

# this function downloads ACLED data
get_acled <- function(country, from, to){
   v <- acled.api( # stores an ACLED sample in object v
     # EMAIL and ACCESS are sensitive information. 
     # Hence, they are stored in a separate file (acled_credentials.R), 
     # which is loaded as an additional source in the beginning of the script. 
      email.address = Sys.getenv("EMAIL_ADDRESS"),
      access.key = Sys.getenv("ACCESS_KEY"),
      country = country,
      start.date = from, 
      end.date = to,
      add.variables = c("longitude","latitude")
      )
 
      # Converts into a spatial object (sf)
      v <- st_as_sf(v, coords=c("longitude","latitude"))
      
      # Defines the event dates as variables of type date
      v$event_date <- as.Date(v$event_date)
      
      # Sets coordinate reference system
      st_crs(v) = 4326

   return(v)
}

# Calls the above defined function and converts the results into an sf object
 acled_17_20_aoi <- get_acled(c("Democratic Republic of Congo","Rwanda","Uganda","Burundi"), "2017-01-01", "2020-12-31") %>% 
  st_as_sf() 

#  Writes the downloaded to hard drive
st_write(acled_17_20_aoi, here("data/geopackages","acled_17_20_aoi.gpkg"), append = TRUE)

```