PURPOSE Krona is a flexible tool for exploring the relative proportions of hierarchical data, such as metagenomic classifications, using a radial, space-filling display. It is implemented using HTML5 and JavaScript, allowing charts to be explored locally or served over the Internet, requiring only a current version of any major web browser. Krona charts can be created using an Excel template or from common bioinformatic formats using the provided conversion scripts. COPYRIGHT LICENSE Copyright © 2011, Battelle National Biodefense Institute (BNBI); all rights reserved. Authored by: Brian Ondov, Nicholas Bergman, and Adam Phillippy This Software was prepared for the Department of Homeland Security (DHS) by the Battelle National Biodefense Institute, LLC (BNBI) as part of contract HSHQDC-07-C-00020 to manage and operate the National Biodefense Analysis and Countermeasures Center (NBACC), a Federally Funded Research and Development Center. Redistribution and use in source and binary forms, with or without modification, are permitted provided that the following conditions are met: * Redistributions of source code must retain the above copyright notice, this list of conditions and the following disclaimer. * Redistributions in binary form must reproduce the above copyright notice, this list of conditions and the following disclaimer in the documentation and/or other materials provided with the distribution. * Neither the name of the Battelle National Biodefense Institute nor the names of its contributors may be used to endorse or promote products derived from this software without specific prior written permission. THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. TRADEMARK LICENSE KRONA™ is a trademark of the Department of Homeland Security, and use of the trademark is subject to the following conditions: * Distribution of the unchanged, official code/software using the KRONA™ mark is hereby permitted by the Department of Homeland Security, provided that the software is distributed without charge and modification. * Distribution of altered source code/software using the KRONA™ mark is not permitted unless written permission has been granted by the Department of Homeland Security. PATENTS The Krona software is not eligible for patent because there have been previous and open implementations of this visualization method since the year 2000 (e.g. "Focus+context display and navigation techniques for enhancing radial, space-filling hierarchy visualizations." Stasko, J. and Zhang, E. InfoVis, 2000). Krona represents a reimplementation and application of an existing method to the new domain of metagenomics. BNBI, as the copyright holders, wish to release Krona freely and openly as a service to the bioinformatics community. POINT OF CONTACT Todd Harrington General Counsel Battelle National Biodefense Institute harringtont@nbacc.net