One can compare Leaves of Grass to Whitman's other published works (a political tome called Democratic Vistas and a novel about alcoholism called Franklin Evans), though his poetry and prose are quite different. While Whitman has inspired many works of art (see the "Bringing in Technology" section), comparing Whitman to other poetry of the time may only serve to show how unique Whitman's work truly is.
It would be interesting to contrast Whitman's poems about the open road with novels about traveling, such as Jack Kerouac's On the Road.
Look at the relationship between Whitman's writing and the writing of the Beat Generation authors, such as Allen Ginsberg, William S. Burroughs, and...