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#95: Development of CF 1.5 Data Model -----------------------------+---------------------------------------------- Reporter: markh | Owner: [email protected] Type: task | Status: new Priority: medium | Milestone: Component: cf-conventions | Version: Resolution: | Keywords: -----------------------------+---------------------------------------------- Comment (by markh): Replying to [comment:43 jonathan]: > ... > Is this the same process as you describe, but in different words? Hello Jonathan I am hoping so, but I'm still not sure. Perhaps I can try to take these terms and cast a practical example, to see whether this fits with your perspective? Consider defining a Field with a 2D array of data, with these data dimensions defined by !DomainAxes and !DimCoords latitude and longitude respectively. My intention is to take a large number of these and run them through an aggregator; the important factor here is defining what I have; the aggregator is out of scope, imo. I have a list of single valued metadata elements which describe my data: height_level, time, forecast_reference_time, forecast_period, ensemble_member, source, institute I need to define appropriate domain_axes and coordinates for these. * source and institute * textual data coordinates * must be !AuxCoords (data type) * no bound domain_axis required * but these may form an aggregating factor at a later date * height_level and time * numerical data coordinates * I want to define their order within the data array * I expect these to be aggregated and I want the order correct * create as !DimCoords * domain_axes are created, at dimensions 2 and 3 respectively * these do not exist in the Field's data array (which is 2D) * forecast_reference_time, forecast_period, ensemble_member * numerical data coordinates * I do not want to define their order within the data array * these may or may not be aggregated over * if they are aggregated, the ordering of dimensions is not important * any one may never be aggregated, and may never define a domain_axis * no domain_axes are created * !DimCoord instances are created and placed in the Field's auxiliary_coords container The times are a crucial factor here, as I have 3 time coordiantes but only 2 degrees of freedom. I never want 3 time related domain_axes, an aggregation operation should return 2 time related domain_axes and 1 2D time coordinate (otherwise my data is faulty); which of the forecast_period or forecast_reference_time becomes a !DomainAxis and !DimCoord is evaluated on inspection, it is data dependent. So, I have a Field with a 2D array of data values (Iy, Ix) 4 domain_axes, ordered (1, 1, Iy, Ix) a dimensions_coords container, with: !DimCoords: time, height_level, latitude, longitude an auxiliary_coords container, with: !DimCoords: forecast_reference_time, forecast_period, ensemble_member !AuxCoords: source, institute Does such a Field instance conform to your view of the CF data model specification? -- Ticket URL: <https://cf-pcmdi.llnl.gov/trac/ticket/95#comment:45> CF Metadata <http://cf-pcmdi.llnl.gov/> CF Metadata This message came from the CF Trac system. To unsubscribe, without unsubscribing to the regular cf-metadata list, send a message to "[email protected]" with "unsubscribe cf-metadata" in the body of your message.
