it wasn't humboldt's expedition https://en.wikipedia.org/wiki/Alexander_von_Humboldt#Spanish... which had nothing to do with the decades-earlier meter-measuring expedition https://en.wikipedia.org/wiki/French_Geodesic_Mission_to_the... (except for being inspired by it) and the contemporary calculations of the paris meridian https://en.wikipedia.org/wiki/History_of_the_metre#M%C3%A8tr...