Beauplan served as artillery captain for the army of the Crown of the Kingdom of Poland between 1630 and 1647 or 1648. He was sent to Ukraine where he served under Stanisław Koniecpolski in 1637–38. He used his architectural skills while in the military. In 1639, he was involved in the rebuilding of the Kodak Fortress. He also built a fortress at Bar, worked on Brody Castle, and structures in Kremenchuk.
In 1639, Beauplan created the first "descriptive" map of Ukraine. He created a map of Ukraine in 1648 that had detailed border information. By 1654 he was working in Danzig. He created a map with a scale of 1:452,000 and an additional map scaled at 1:1,800,000. Both maps were engraved by Willem Hondius. These maps would go on to be published in Rouen, France and reproduced by Veniiamyn Kordt. Beauplan published another map of the Dnieper River in 1662.
He wrote Description des contrés du Royaume de Pologne, which was published in 1651. It was renamed Description d'Ukranie, when the second edition was released in 1651. Two more editions were published in 1660 and 1861. The book was the first book published that provided a geographical, economic, and demographic description of Ukraine. By 1832 it had been translated into five languages. It remains in print today. In the book, Ukraine was described as a territory between Muscovy and Transylvania.
- Beauplan, Guillaume Le Vasseur, sieur de (1861). Description de l'Vkranie depvis les confins de la Moscovie jvsqu'avx limites de la Transylvanie. Paris: J. Techner.CS1 maint: multiple names: authors list (link), Internet Archive
- "General Depiction of the Empty Plains (in Common Parlance, the Ukraine) Together with its Neighboring Provinces". World Digital Library. Retrieved 20 January 2013.
- Borschak, Elie. "Beauplan, Guillaume Le Vasseur de". Internet Encyclopedia of Ukraine. Retrieved 20 January 2013.
- Media related to Guillaume le Vasseur de Beauplan at Wikimedia Commons
- Dennis F. Essar, Andrew B. Pernal: Beauplan’s Description d’Ukranie. A Bibliography of Editions and Translations. Harvard Ukrainian Studies VI, 4 (1982), S. 485–499 (PDF).
- Guillaume Le Vasseur de Beauplan at WorldCat
- Beauplan's bio at the website of French Ambassador to Ukraine