  Integration of scalar and vector visualization has been an interesting topic.
This paper presents a technique to appropriately select and display multiple
streamlines while overlaying with isosurfaces, aiming an integrated scalar and
vector field visualization. The technique visualizes a scalar field by multiple
semitransparent isosurfaces, and a vector field by multiple streamlines, while
the technique adequately selects the streamlines considering reduction of
cluttering among the isosurfaces and streamlines. The technique first selects
and renders isosurfaces, and then generates large number of streamlines from
randomly selected seed points. The technique evaluates each of the streamlines
according to their shapes on a 2D display space, distances to critical points
of the given vector fields, and occlusion by isosurfaces. It then selects the
specified number of highly evaluated streamlines. As a result, we can visualize
both scalar and vector fields as a set of view-independently selected
isosurfaces and view-dependently selected streamlines.
