Hi folks,

I'm working on a format for storing the output from a particle tracking model. Once we're happy with it, we'll post here for feedback, but for the moment a question:

As many particle tracking models create and destroy particles as the run goes on, we have decided that a "ragged array" representation is the way to go. But I'm having trouble figure out the "standard" way to represent ragged arrays. An minimal example:


dimensions:
        time = 24 ;
        data = UNLIMITED ; // (240 currently)

## The data dimension describes the "ragged array" -- it is stored as a 1-d array

## time is straightforward.

variables:
        double time(time) ;
                time:units = "seconds since 1970-01-01 0:00:00" ;
                time:long_name = "time" ;
                time:standard_name = "time" ;
        int particle_count(time) ;
                particle_count:units = "1" ;
                particle_count:long_name = "number of particles in a given 
timestep" ;
                particle_count:CF:ragged_row_count = "data" ;

## here is the question. particle_count is the number of particles at each time step -- this describes how long each "row" of the ragged array is. For each time step, it gives the number of particles at that time.

I also found this in the CDM implementation of CF discrete sampling features (DRAFT):

"ragged_row_count is an alias for sample_dimension standard name"

so should we be using "sample_dimension" instead? ( I like ragged_row_count better, this isn't a sample )

Is the the way to specify a "ragged array?"

-Chris








--
Christopher Barker, Ph.D.
Oceanographer

Emergency Response Division
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