12 Sep 2016

Hashedcubes: Simple, Low Memory, Real-Time Visual Exploration of Big Data

Cicero A. L. Pahins, Sean A. Stephens, Carlos Scheidegger, Joao L. D. Comba. IEEE InfoVis 2016.

We propose Hashedcubes, a data structure that enables real-time visual exploration of large datasets. It improves the state of the art by virtue of its low memory requirements, low query latencies, and implementation simplicity. In some instances, Hashedcubes notably requires two orders of magnitude less space than recent data cube visualization proposals. In this paper, we describe the algorithms to build and query Hashedcubes, and how it can drive well-known interactive visualizations such as binned scatterplots, linked histograms and heatmaps.

We report memory usage, build time and query latencies for a variety of synthetic and real-world datasets, and find that although sometimes Hashedcubes offers slightly slower querying times to the state of the art, the typical query is answered fast enough to easily sustain a interaction. In datasets with hundreds of millions of elements, only about 2% of the queries take longer than 40ms. Finally, we discuss the limitations of the data structure, potential spacetime tradeoffs, and future research directions.

Paper in PDF format.