[2] She continued to work with Ratzel and produced several academic papers in American and European journals, but was never conferred a degree.

[3] She was the first female faculty member, teaching graduate students in geography for the next decade, but her salary was always significantly less than her male colleagues.

Influenced by the works of Charles Darwin and inspired by her mentor Freidrich Ratzel, Semple theorized that human activity was primarily determined by the physical environment.

Although environmental determinism is today heavily critiqued and has lost favor in social theory, it was widely accepted in academia in the late 19th-early 20th centuries.

In a series of books and papers she communicated certain aspects of the work of German geographer Friedrich Ratzel to the Anglophone community.

In her work Influences of Geographic Environment on the Basis of Ratzel's System of Anthropo-Geography (1911), she describes people and their associated landscapes, dividing the world into key environmental types.

Semple identifies four key ways that the physical environment is affected: 1) direct physical effects (climate, altitude); 2) psychical effects (culture, art, religion); 3) economic and social development (resources and livelihoods); 4) movement of people (natural barriers and routes, such as mountains and rivers).

[2][3] From 1911 to 1912, she undertook an eighteen-month journey which visited Japan, Korea, China, the Philippines, Java, Ceylon, India, Egypt, Palestine, Lebanon, and Turkey in addition to places in Europe and the United States.

[5] During her fieldwork, she took notes on human-environment relations, cultural features of the landscape, and made detailed observations of housing, structures, livelihoods, and daily life.