Book Image

Time Series Indexing

By : Mihalis Tsoukalos
Book Image

Time Series Indexing

By: Mihalis Tsoukalos

Overview of this book

Time series are everywhere, ranging from financial data and system metrics to weather stations and medical records. Being able to access, search, and compare time series data quickly is essential, and this comprehensive guide enables you to do just that by helping you explore SAX representation and the most effective time series index, iSAX. The book begins by teaching you about the implementation of SAX representation in Python as well as the iSAX index, along with the required theory sourced from academic research papers. The chapters are filled with figures and plots to help you follow the presented topics and understand key concepts easily. But what makes this book really great is that it contains the right amount of knowledge about time series indexing using the right amount of theory and practice so that you can work with time series and develop time series indexes successfully. Additionally, the presented code can be easily ported to any other modern programming language, such as Swift, Java, C, C++, Ruby, Kotlin, Go, Rust, and JavaScript. By the end of this book, you'll have learned how to harness the power of iSAX and SAX representation to efficiently index and analyze time series data and will be equipped to develop your own time series indexes and effectively work with time series data.
Table of Contents (11 chapters)

Using icicle plots

In this section, we are going to discuss a different kind of plot, which is called an icicle plot. An icicle plot is a method for presenting hierarchical clustering and is able to visualize hierarchical data using rectangular sectors that go from the root node to the leaves. In our case, we are going to use a zoomable icicle plot.

First, please go to the ZoomableIcicle directory and replace the JSON file in files with 100k.json. This time, instead of changing the JavaScript code, we are going to change the field name of the JSON file from size to value. In general, it is better to change your input data than the code.

Figure 6.9 shows a part of the generated icicle visualization. The rectangle on the left side represents the root node, which contains 99,985 subsequences – this is the total number of subsequences stored in the iSAX index.

Figure 6.9 – Visualizing iSAX using an icicle

Figure 6.9 – Visualizing iSAX using an icicle

Apart from the SAX representation...