This message came from the CF Trac system. Do not reply. Instead, enter your comments in the CF Trac system at https://cf-pcmdi.llnl.gov/trac/.
#104: Clarify the interpretation of scalar coordinate variables -----------------------------+---------------------------------------------- Reporter: jonathan | Owner: [email protected] Type: enhancement | Status: new Priority: medium | Milestone: Component: cf-conventions | Version: Resolution: | Keywords: -----------------------------+---------------------------------------------- Comment (by jonathan): Dear Mark Concerning the example {{{ dimensions: sample = 39238923; variables: float data(sample); data:coordinates = "lat lon time"; float lat; float lon; float heightAboveGround ; float heightAboveMsl; float time(sample); }}} I would say this is not an ideal way of storing this data. I agree that, according to this ticket, it implies five independent dimensions. It is not illegal, but it is likely that it doesn't really describe the data's logical structure properly (of course, I am guessing at what the true situation is), in two ways: * The `sample` dimension is really an independent coordinate of time. So a 1D (dimension) coordinate variable should be used for this, not an auxiliary. * Height above ground and height above MSL are necessarily related. The above does not show their relationship. Therefore, I think this data should probably be stored like this instead: {{{ dimensions: sample = 39238923; heightAboveGround=1; variables: float data(time,heightAboveGround); data:coordinates = "lat lon heightAboveMsl"; float lat; float lon; float heightAboveGround(heightAboveGround) ; float heightAboveMsl(heightAboveGround); float time(time); }}} or the roles of `heightAboveGround` and `heightAboveMsl` could be exchanged. The data actually has four independent coordinates, and one dependent coordinate. If we adopt this ticket, the interpretation is umambiguous. The original version has a different interpretation. It might cause a nuisance to the analyst that the dependencies had not been indicated in the file, but it shouldn't be hard to fix it up when the data is being processed. As in previous discussions, I would argue that adopting this ticket doesn't make anything illegal which is currently legal, but in some cases it may lead to data-writers being clearer about their intentions, and that's a good thing, I would say. Cheers Jonathan -- Ticket URL: <https://cf-pcmdi.llnl.gov/trac/ticket/104#comment:49> 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.
