"In later life, David Thompson habitually signed himself ‘Astronomer and Surveyor Under the 6th and 7th Articles of the Treaty of Ghent.’ It is telling that Thompson identified more closely with this role, which he held from 1817 to 1827, than with the work on which his fame rests today: his fur trade career with the Hudson’s Bay Company and the North West Company, lasting from 1784 to 1812. In one respect, Thompson’s use of the title was self-interested, as it emphasizes work performed on behalf of his country (service meaningful to the political and commercial figures with which he corresponded, and whose patronage he often sought), and elides the ambiguous legacy of his departure from the HBC, and the demise of the NWC, in which he had been a partner. But the term also reflects Thompson’s conception of himself as one who engaged in the scientific pursuits of observing the heavens, measuring the land, and using the data he obtained to create maps."
http://www.library.utoronto.ca/fisher/exhibitions/thompson/
http://www.library.utoronto.ca/fisher/exhibitions/thompson/