OD Maps are a novel technique for showing spatial patterns in flows between origins and destinations in a non-occluding fashion. They are actually simply reordered OD matrices.
This video explains how they work, using county-county migration in Ireland, based on work we have done with Mary Kelly (NUI Maynooth).
See our paper "Visualisation of Origins, Destinations and Flows with OD Maps" for more details
The graphics were done in HiDE (gicentre.org/hide/)