Streamlines and Streamsurfaces are standard tools for the visual analysis of flow data. Nevertheless, their applications still poses challenges concerning their extraction, integration, and visualization. In the talk, we tackle three problems: (1) the selection of suitable stream lines, (2) a stable integration of stream surfaces and (3) the selection of suitable stream surfaces. We show that these problems can and should be formulated as global optimization problems. We present the respective error functionals to be minimized and show solutions for several test cases.