elevation download and processing

R/get_elevation.R

@@ -7,11 +7,31 @@
 #' @return
 #' @author Whitney Bagge
 #' @export
-get_glw <- function() {
+library(paws)
+get_elevation<- function(elevation_directory_raw, overwrite=FALSE) {
 
-  url_cattle <- "https://dataverse.harvard.edu/dataset.xhtml?persistentId=doi:10.7910/DVN/LHBICE#"
-  url_cattle_out <- GET(url_cattle)
-  unzipped_glw_cattle <- unzip(url_cattle_out)
-  Aw_layer <- if_else(str_detect(names(unzipped_glw_cattle), "Aw")==TRUE, )
+  existing_files <- list.files(elevation_directory_raw)
+
+  download_filename <- tools::file_path_sans_ext(existing_files)
+
+  save_filename <- paste0(download_filename, ".tif")
+
+  message(paste0("Downloading ", download_filename))
+
+  if(save_filename %in% existing_files & !overwrite) {
+    message("file already exists, skipping download")
+    return(file.path(elevation_directory_raw, save_filename)) # skip if file exists
+  }  
+
+  s3_svc <- s3(config = list(region = "af-south-1",  credentials = list(anonymous = TRUE)))
+  # Download the file directly to disk in the current working directory
+  s3_svc$download_file(
+    Bucket = "deafrica-input-datasets",
+    Key = "srtm_dem/srtm_africa.tif",
+    Filename = "data/elevation/srtm_africa.tif"
+  )
+
+
+  return(elevation_directory_raw)
 
 }

R/process_elevation.R

@@ -7,11 +7,20 @@
 #' @return
 #' @author Whitney Bagge
 #' @export
-process_elevation <- function(elevation_layer_raw, bounding_boxes) {
+process_elevation<- function(elevation_directory_raw, elevation_directory_dataset, elevation_downloaded, continent_raster_template) {
 
-  extent_object <- extent(bounding_boxes)
-  elevation_layer_raw_out <- crop(elevation_layer_raw, extent_object)
 
-  return(elevation_layer_raw_out)
+  transformed_raster <- transform_raster(raw_raster = rast("data/elevation/srtm_africa.tif"),
+                                            template = rast(continent_raster_template))
+
+  # Convert to dataframe
+  dat_out2 <- as.data.frame(transformed_raster, xy = TRUE) |> 
+    as_tibble() 
+
+  # Save as parquet 
+  write_parquet(dat_out2,  "data/elevation_dataset/elevation_dataset", compression = "gzip", compression_level = 5)
+
+
+  return(elevation_directory_dataset)
 
 }