Understanding the Burrows-Wheeler Transform: An Interactive Guide to Data Compression and Sequence Alignment

Summary

This article provides an interactive introduction to the Burrows-Wheeler Transform (BWT), explaining its core concepts and practical applications. It covers how the BWT works by creating rotations of input strings, sorting them, and extracting the last column to create the transformed output. The article explains the importance of the dollar sign ($) as an end-of-string marker that makes the transformation reversible, particularly important for applications like DNA sequence alignment where multiple rotations may look equally valid. The content explores the intuition behind why BWT works for compression - that sorting causes similar contexts to group together, creating runs of identical characters that are easier to compress.