A survey is an activity, within a specific geographical area and time frame, during which one or more types of geophysical data are acquired.
A processing/reprocessing is an activity resulting in a set of processed data, based on field data acquired on one or more surveys. A processing is made by a specific company, within a specific time frame. It does not necessarily cover the entire surveyed area.
A data set from a processing consists of data types which may include stacked and/or migrated data, velocity data, navigation data etc.
If a processing is released, and the data set is available, this may be purchased from GEUS.
Data acquired on several surveys may be joined during processing to create a new reprocessing called a merge.