This software package, developed at the University of Illinois at Urbana-Champaign and the University of Oklahoma, allows processing of optical array probe (OAP) datasets. The code originated from an IDL code developed at the National Center for Atmospheric Research by Bill Hall in 1998, which was subsequently modified by Aaron Bansemer. The current version of the code was brought to the University of Illinois in 2001 by Greg McFarquhar, converted to MATLAB by Matt Freer, and then subsequently modified and updated by Robert Jackson, Wei Wu, Joe Finlon and Dan Stechman. The code was moved to the University of Oklahoma in 2017 by the University of Oklahoma.