wikidata

Wikidata is a free and open knowledge base that can be read and edited by both humans and machines.

Wikidata acts as central storage for the structured data of its Wikimedia sister projects including Wikipedia, Wikivoyage, Wiktionary, Wikisource, and others.

• https://www.wikidata.org/wiki/Wikidata:List_of_properties/science

• https://www.wikidata.org/wiki/Q597

Query ICAO codes

• https://query.wikidata.org/#SELECT%20%3Fitem%20%3FitemLabel%20%3Fid%20WHERE%20%7B%0A%20%20%3Fitem%20wdt%3AP239%20%3Fid%0A%20%20SERVICE%20wikibase%3Alabel%20%7B%20bd%3AserviceParam%20wikibase%3Alanguage%20%22%5BAUTO_LANGUAGE%5D%2Cen%22.%20%7D%0A%7D

SELECT ?item ?itemLabel ?id WHERE {
  ?item wdt:P239 ?id
  SERVICE wikibase:label { bd:serviceParam wikibase:language "[AUTO_LANGUAGE],en". }
}

SELECT DISTINCT ?id WHERE {
  ?item wdt:P239 ?id
  SERVICE wikibase:label { bd:serviceParam wikibase:language "[AUTO_LANGUAGE],en". }
} ORDER BY ?id 

Query IATA codes

SELECT ?item ?itemLabel ?id WHERE {
  ?item wdt:P238 ?id
  SERVICE wikibase:label { bd:serviceParam wikibase:language "[AUTO_LANGUAGE],en". }
}

SELECT DISTINCT ?id WHERE {
  ?item wdt:P238 ?id
  SERVICE wikibase:label { bd:serviceParam wikibase:language "[AUTO_LANGUAGE],en". }
} ORDER BY ?id 

Get items that are instances of cities of Portugal

SELECT ?item ?itemLabel WHERE {
  ?item wdt:P31 wd:Q15647906
  SERVICE wikibase:label { bd:serviceParam wikibase:language "pt". }
}