  As an effective form of narrative visualization, visual data stories are
widely used in data-driven storytelling to communicate complex insights and
support data understanding. Although important, they are difficult to create,
as a variety of interdisciplinary skills, such as data analysis and design, are
required. In this work, we introduce Erato, a human-machine cooperative data
story editing system, which allows users to generate insightful and fluent data
stories together with the computer. Specifically, Erato only requires a number
of keyframes provided by the user to briefly describe the topic and structure
of a data story. Meanwhile, our system leverages a novel interpolation
algorithm to help users insert intermediate frames between the keyframes to
smooth the transition. We evaluated the effectiveness and usefulness of the
Erato system via a series of evaluations including a Turing test, a controlled
user study, a performance validation, and interviews with three expert users.
The evaluation results showed that the proposed interpolation technique was
able to generate coherent story content and help users create data stories more
efficiently.
