Data Model - appearance to applications

The JGOFS data model is the critical part of the communications protocol. It includes:

Comments (text)
Variable descriptions
- Name
- Dimensions for vectors/ matrices/ tensors [not implemented!]
- Attributes (e.g., units)
- Hierarchical structure
Data
- Strings or numbers
End of data set indicator

The hierarchical structuring is an important way of organizing many kinds of data. It groups the least rapidly changing variables (e.g., header data), then the next-most rapidly changing information, etc. For example, a hydrographic section might look like

leg
year          [lowest (0) level]
month
   station
   lat        [level 1]
   lon
   date
      press
      temp
      sal     [level 2]
      o2
      sigth

A current meter mooring might have

mooring_id
lat
lon                 [level 0]
nominal_depth
start_time
end_time
   time
   u                [level 1]
   v
   temp

Often one scans the lower level information first to pick out the desired station or mooring and then retrieves the information only for that subset of the data base.