atmqty Manual: Difference Between AtmQty and CDAT

Because both the AtmQty class and classes in the Climate Data Analysis Tool (CDAT) organize data using Numeric arrays, it is not that difficult to transform AtmQty and CDAT objects into one another. CDAT objects, however, tend to be more complete than AtmQty objects, with a full suite of variable specific metadata.

CDAT objects are usable for a variety of climate related applications while AtmQty is used only for handling non-time-integrated atmospheric quantities. The focus of an AtmQty object is easy management of the interrelatedness and derivativeness of the quantities: quantities in the object all share the same grid and are related to one another in that derivative quantities are based on the same input state variables. Finally, the data model for quantities in AtmQty is more basic than the MV model used in CDAT objects; missing values in AtmQty are specified by a missing value in the data array instead of a mask attribute.