WALCOM: Algorithms and Computation
 Anthology ID:
 G2210
 Month:
 Year:
 2022
 Address:
 Venue:
 GWF
 SIG:
 Publisher:
 Springer International Publishing
 URL:
 https://gwfuwaterloo.github.io/gwfpublications/G2210
 DOI:
StreamTable: An Area Proportional Visualization forÂ Tables withÂ Flowing Streams
Jared Espenant

Debajyoti Mondal
AbstractLet M be a twodimensional table with each cell weighted by a nonzero positive number. A StreamTable visualization of M represents the columns as nonoverlapping vertical streams and the rows as horizontal stripes such that the intersection between a stream and a stripe is a rectangle with area equal to the weight of the corresponding cell. To avoid large wiggle of the streams, it is desirable to keep the consecutive cells in a stream to be adjacent. Let B be the smallest axisaligned bounding box containing the StreamTable. Then the difference between the area of B and the sum of the weights is referred to as the excess area. We attempt to optimize various StreamTable aesthetics (e.g., minimizing excess area, or maximizing cell adjacencies in streams). If the row permutation is fixed and the row heights are given, then we give an O(rc)time algorithm to optimizes these aesthetics, where r and c are the number of rows and columns, respectively. If the row permutation is fixed but the row heights can be chosen, then we discuss a technique to compute an aesthetic (but not necessarily optimal) StreamTable by solving a quadraticallyconstrained quadratic program, followed by iterative improvements. If the row heights are restricted to be integers, then we prove the problem to be NPhard. If the row permutations can be chosen, then we show that it is NPhard to find a row permutation that optimizes the area or adjacency aesthetics. KeywordsGeometric AlgorithmsTable CartogramStreamgraphs