Conceived on a grand scale with crystalline logic, mathematical precision, and environmental intent, Agnes Denes’s grandiose visionary projects never quite fit the labels. When she planted (and harvested) two acres of corn in Lower Manhattan in 1982 on the Battery Park landfill, she was out in left field. Her paradoxical mix of Earthworks and Land Art with narrative, social, economic, and ecological issues (urban, rural, global) was a bit much. Ranging from Rice/Tree/Burial (a planting and time capsule) in the ’70s and the undulating pyramids and nautilus structures she envisioned in the ’80s to Tree Mountain (11,000 trees, 11,000 people, 400 years) in Finland in the ’90s and an installation of live sheep on the grounds of the venerable American Academy in Rome a few years ago, her work remained underrated, or at least out of sync with the times. Its false affinities to structural fantasists Will Insley or Charles Simonds and terrain wrappers Christo and Jeanne-Claude didn’t help, nor did her own overly exalted writings. Finally the Chelsea Art Museum does a museum-worthy show and rectifies that. This retrospective presents evidence (drawings, computer renderings, models, photographs) not only of 63 projects, built and unbuilt, but of the impressive scope of her vision.