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Internally, a single 2D or 3D scalar data field (i.e., one forecast variable, one time step, one ensemble member) is treated as the smallest data entity. A single data field is stored in a class derived from MStructuredGrid, these objects store all contextual information required to visualise the field (including latitude and longitude coordinates, pressure or hybrid level, time step and additional metadata). Example of derived classes are MRegularLonLatGrid for 2D fields, MRegularLonLatStructuredPressureGrid for 3D fields on pressure levels, MLonLatHybridSigmaPressureGrid for 3D fields on hybrid sigma-pressure levels. Time series and ensemble sets are composed of these basic data field entities.
- https://gitlab.com/wxmetvis/met.3d/-/blob/master/src/data/structuredgrid.h
- https://gitlab.com/wxmetvis/met.3d/-/blob/master/src/data/structuredgrid.cpp
Trajectory data
Trajectories are stored as bundles of trajectories (class MTrajectories). A single trajectory in a bundle consists of a simple list of positions in longitude-latitude-pressure space that resemble the trajectory. All trajectories in a bundle share the same time information, i.e. the time for position n is the same for all trajectories. This data layout corresponds to the smallest data entity being the bundle of all trajectories computed for a single ensemble member for the same time steps.