Monday, July 19, 2010

BigWig and BigBed: enabling browsing of large distributed data sets

Summary: BigWig and BigBed files are compressed binary indexed files containing data at several resolutions that allow the high-performance display of next-generation sequencing experiment results in the UCSC Genome Browser. The visualization is implemented using a multi-layered software approach that takes advantage of specific capabilities of web-based protocols and Linux and UNIX operating systems files, R trees, and various indexing and compression tricks. As a result, only the data needed to support the current browser view is transmitted rather than the entire file, enabling fast remote access to large distributed data sets.

Availability and Implementation: Binaries for the BigWig and BigBed creation and parsing utilities may be downloaded at Source code for the creation and visualization software is freely available for noncommercial use at, implemented in C and supported on Linux. The UCSC Genome Browser is available at


Supplementary Information: Supplementary byte-level details of the BigWig and BigBed file formats are available at Bioinformatics online. For an in-depth description of UCSC data file formats and custom tracks, see and

(this Post content was reproduced from:, Via Bioinformatics - Advance Access.)