SAX Navigator: Time Series Exploration through Hierarchical Clustering
This is an incremental improvement for data analysts working with time series, providing a tool to navigate and scrutinize clustered data more effectively.
The paper tackles the challenge of exploring large collections of time series data by developing SAX Navigator, an interactive visualization tool that uses hierarchical clustering and a pattern vocabulary based on Symbolic Aggregate approXimation (SAX) to enable efficient analysis, as demonstrated through case studies and a usability study with an astronomy domain scientist.
Comparing many long time series is challenging to do by hand. Clustering time series enables data analysts to discover relevance between and anomalies among multiple time series. However, even after reasonable clustering, analysts have to scrutinize correlations between clusters or similarities within a cluster. We developed SAX Navigator, an interactive visualization tool, that allows users to hierarchically explore global patterns as well as individual observations across large collections of time series data. Our visualization provides a unique way to navigate time series that involves a "vocabulary of patterns" developed by using a dimensionality reduction technique,Symbolic Aggregate approXimation(SAX). With SAX, the time series data clusters efficiently and is quicker to query at scale. We demonstrate the ability of SAX Navigator to analyze patterns in large time series data based on three case studies for an astronomy data set. We verify the usability of our system through a think-aloud study with an astronomy domain scientist.