Konza Prairie Weirs

Fetches and saves weir monitoring images from the Konza Prairie LTER stream gauging stations. The script checks the server's Last-Modified header before downloading and skips the download if the local files are already current.

Latest Discharge

Overview

weir_download.R does three things:

1. Check — sends a HEAD request to the server and reads the Last-Modified header for the stage image.
2. Compare — finds the most recently saved *_weir_stage.png in pics/ and compares its filesystem mtime to the server timestamp.
3. Download — only fetches both images (stage and discharge) if the server has newer data, then saves them as dated PNGs (YYYYMMDD_weir_stage.png / YYYYMMDD_weir_discharge.png) and stamps the files with the server's modification time.

Dependencies

if (!requireNamespace("pak", quietly = TRUE)) {
  install.packages("pak")
}

pak::pak(c(
  "cli",
  "magick",
  "httr2",
  "lubridate"
))

Usage

source("weir_download.R")

Output files are written to pics/.