SATURN OMX was originally developed with Citilabs CUBE software in 2015 for use by Transport for London and made available to all users as part of SATURN 11.3.12W. The SATURN / CUBE implementation used an extension to the original data standard to handle stacked matrices and support hierarchical zone systems. The SATURN / CUBE-based OMX data format was interchangeable between CUBE v6.4.2/3 and SATURN 11.3.12W to 11.5.04T Beta inclusive.
Following the publication of the v0.2 OMX specification, an updated OMX implementation was developed and made available from SATURN 11.5.05 onwards. NB: the new v0.2 specification SATURN OMX files are not compatible with previous versions.
There are two batch files available to convert from .UFM format to .OMX format (UFM2OMX.BAT) and vice versa (OMX2UFM.BAT) as described in sections 10.20.28 and 10.20.27 respectively. [NB: No interactive options are currently available].
UFM2OMX will currently write out an OMX for a matrix with either one block, i.e. a normal "stacked" matrix, with one OMX table for each UFM level, or one level and multiple blocks (historically a time-period matrix). See 10.2.4.
The new 11.5 charging area matrices that are both multi-level and blocked pose a problem. Operationally, the storage method of UFMs is optimised for how SATURN uses the data, and the conversion to OMX format is hampered by internal storage limitations. If required, (as for more complicated analyses) matrices will need to be broken up first by either using MXUNBLOCK (see 10.20.29) or unstacked into single user class matrices.
OMX2UFM currently reads all the OMX tables into a UFM as a single block with multiple levels, each level corresponding to a table. However, the user must take care to then manipulate the resulting UFM as the levels are in alphabetic sort order of the OMX table names - this was what the extension to the original standard attempted to avoid. Further work is underway to resolve this issue, but the benefits of using OMX to transfer matrix information are such that the current versions are being made available.