1. A method comprising: obtaining a first set of measurements of distances between nodes located on a seismic spread element while in tow using a first set of one or more sources; obtaining a second set of measurements of the distances using a second set of one or more sources; and determining a three-dimensional structure of the seismic spread element while in tow based at least in part on selectively weighted contributions of the first and second sets of measurements, the determining comprising modeling the first and second sets of measurements of distances as an over-determined system.