I was involved from the survey planning, right through ground truthing field work and data collection (in the aircraft it was 7 hour low level flights at 1500 feet about 3 times a week), data processing and collation and final data collation into the formal survey reports and also the 3D visualisation. We had a real time 3D fly through system developed in the late 90s. That could cope with three months of data at once - serious mini-mainframe computer power there.  Some info about it here:
http://www.hydro.gov.au/aboutus/lads/lads-how.htm