  Sports visualization has developed into an active research field over the
last decades. Many approaches focus on analyzing movement data recorded from
unstructured situations, such as soccer. For the analysis of choreographed
activities like formation dancing, however, the goal differs, as dancers follow
specific formations in coordinated movement trajectories. To date, little work
exists on how visual analytics methods can support such choreographed
performances. To fill this gap, we introduce a new visual approach for planning
and assessing dance choreographies. In terms of planning choreographies, we
contribute a web application with interactive authoring tools and views for the
dancers' positions and orientations, movement trajectories, poses, dance floor
utilization, and movement distances. For assessing dancers' real-world movement
trajectories, extracted by manual bounding box annotations, we developed a
timeline showing aggregated trajectory deviations and a dance floor view for
detailed trajectory comparison. Our approach was developed and evaluated in
collaboration with dance instructors, showing that introducing visual analytics
into this domain promises improvements in training efficiency for the future.
