netCDF OarS conventions

• To: netcdfgroup@xxxxxxxxxxxxxxxx
• Subject: netCDF OarS conventions
• From: kegp@xxxxxxxxxxxxx (k.prada)
• Date: Mon, 28 Sep 1992 10:22:37 EDT

Tim Holt wrote concerning OarS/BoaT:

> QUESTION:  The Compliance list contains the statement: "All data sets
> should be configured in four dimensions."  My question is this:  do you
> expect the data from each instrument to have 4 dimensions (I assume X,
> Y, Z, and Time), or can some be globals?  I'll pose the following
> example and tell me if it's what you have in mind.  Assume the following
> instruments...


While OarS suggests the use of four dimensions, it does not require
all dimensions be used with every variable.  Nor is it necessary 
that all dimensions have sizes greater than one (there will generally be an
unlimited dimension). We expect that most data classes will use a combination
of single and four dimensioned variables.

The following cdl script is how I would handle your described data for OarS:

dimensions:
  time = unlimited;
  x    = 1;
  y    = 1;
  bins = 40;

variables:
  long  time(time);                 // clock value
  float gps_lat(time);              // latitude
  float gps_lon(time);              // longitude
  float air_temp(time);             // air temperature
    air_temp:level = 0.0;           // sea level for air temperature
  float sea_temp(time);             // sea temperature
    sea_temp:level = 5.0;           // 5 meter depth for sea temperature
  float n_s_vector(time,bins,x,y);  // adcp n_s for 40 bins
    n_s_vector:bin_size = "5.0m";   // bin size is 5 meters
  float e_w_vector(time,bins,x,y);  // adcp e_w for 40 bins
    e_w_vector:bin_size = "5.0m";   // bin size is 5 meters

Latitude and longitude are stored variables and do not describe the shape
of this data set.  The adcp uses four dimensions while the other variables
use a single dimension (unlimited).

Let me emphasize that the draft version of conventions is just that, a draft.
There are details that are either inferred or missing at this time.  These
recent comments are already helping refine our ideas.  We welcome them.

___________________________________________________________________________
            Ken Prada                 |
Applied Ocean Physics and Engineering |Organization is critical to success.
Woods Hole Oceanographic Institution  |
       (508) 457-2000 Ext 2711        |Try eating a soup sandwich.
          kegp@xxxxxxxxxxxxx          |