Area of different BioBlitzes in the Biodiversity Challenge 2025 on Observation.org

bioblitzes_area.csv

index.js

const { promises: fs, existsSync: exists } = require('fs')
const path = require('path')

const { JSDOM } = require('jsdom')
const turf = require('@turf/turf')

const CACHE_FILE = path.join(__dirname, 'cache.json')
let cache
async function fetchText (url, options) {
  if (!cache) {
    if (exists(CACHE_FILE)) {
      cache = JSON.parse(await fs.readFile(CACHE_FILE, 'utf8'))
    } else {
      cache = {}
    }
  }

  if (cache.hasOwnProperty(url)) {
    // console.error('Using cache...')
  } else {
    console.error('Fetching over HTTP...', url)
    cache[url] = await fetch(url, options).then(response => response.text())
  }

  return cache[url]
}

async function fetchHtml (url, options) {
  return fetchText(url, options).then(text => (new JSDOM(text, { url })).window.document)
}

async function main () {
  const index = await fetchHtml('https://observation.org/bioblitz/categories/biodiversity-challenge-2025/')
  const bioblitzes = index.querySelectorAll('table tbody td:nth-child(2) a')

  const table = []
  for (const bioblitz of bioblitzes) {
    const map = await fetchHtml(bioblitz.href)
    const geojson = JSON.parse(map.getElementById('geojson').textContent)
    const area = turf.area(geojson)
    table.push({ name: bioblitz.textContent, area })
  }
  table.sort((a, b) => b.area - a.area)

  console.log(['BioBlitz', 'Area (km2)'].join())
  for (const { name, area } of table) {
    console.log([name, Math.floor(area / 1e4) / 1e2].join())
  }
}

main().catch(console.error).finally(() => {
  return fs.writeFile(CACHE_FILE, JSON.stringify(cache, null, 2))
})