Steve, I like this suggestion. It's more forward-looking, just as easy to implement, and still solves the problem that we were trying to solve with "ocean_binary_mask", which was to make it easy for providers to make their data CF-compliant.
-Rich On Mon, Jan 3, 2011 at 3:34 PM, Steve Hankin <[email protected]> wrote: > Trial balloon: > > This conversation circles around the idea of masks that serve a > discipline-specific purpose: a land mask for terrestrial types; or a sea > mask for ocean types. Each discipline finds it natural to have "1" indicate > valid points for his particular outlook. It will always be an effort for > the data providers in one discipline to adopt the conventions of another. > > One could imagine masks for other (less common) purposes as well in which > the 1's signify other things. For example there are valid uses for time > masking, in which the 1's would indicate valid time indices. Perhaps the > fact that this conversation is occurring illustrates that we should be > approaching masking in a discipline-neutral way -- defining a new attribute, > and a more generic new standard_name. Something like: > > netcdf mask_eg { > dimensions: > AX003 = 10 ; > AX002 = 20 ; > variables: > float LON_U(AX002, AX003) ; > LON_U:long_name = "curvilinear longitudes" ; > LON_U:units = "degrees_north" ; > float LAT_U(AX002, AX003) ; > LAT_U:long_name = "curvilinear latitudes" ; > LAT_U:units = "degrees_east" ; > float U(AX002, AX003) ; > U:coordinates = "LAT_U LON_U" ; > U:_FillValue = -1.e+34f ; > U:long_name = "Zonal Velocity" ; > U:units = "meters/sec" ; > U:binary_mask = "U_MASK"; > float U_MASK(AX002, AX003) ; > U_MASK:coordinates = "LAT_U LON_U" ; > U_MASK:standard_name = "binary_mask" ; // "1" indicates valid > U_MASK:long_name = "Ocean mask" ; > > // global attributes: > :Conventions = "CF-1.5" ; > > } > > Is this a preferable approach? > > - Steve > > =========================== > > On 1/3/2011 11:35 AM, Rich Signell wrote: > > Chris, > > On Mon, Jan 3, 2011 at 12:57 PM, Christopher Barker > <[email protected]> wrote: > > On 1/2/11 6:11 PM, Rich Signell wrote: > > But they are not the same thing. They are the inverse. > > yes, of course, but they carry exactly the same information, do they not. > > Yes, one could be inferred from the other. > > Why have two ways to express the same information? > > Yes, it would > be possible to have data sets providers create NcML for every ROMS > dataset that has ever been written and serve the data with a > land_binary_mask instead of a sea_binary_mask. > > well, I suppose it may be a question of whether there are more data > providers or data consumers... > > Since most consumers use some kind of tool, I would says it's more a > question of whether there are more data providers or more CF-compliant > tool developers. And since many tool developers use NetCDF-Java or > some other package to enable CF compliance, perhaps there are really > not so many software changes to be made. > > That also implies that there are a bunch of ROMS-output netcdf files that > already have a sea_binary_mask variable, and are therefor not currently > CF-compliant. Is that the case? Do we want to add things to the standard to > make common, but not compliant, use cases compliant? Perhaps so. > > I think "Perhaps so" is exactly right. The advantage of making it > easier for providers to standardize their datasets vs the additional > burden to CF-compliant tool developers. > > -Rich > > > On Sun, Jan 2, 2011 at 12:31 PM, Chris Barker<[email protected]> > wrote: > > On 12/30/2010 2:40 PM, Rich Signell wrote: > > CF Standard Name Team: > > I would like to request a new standard_name="sea_binary_mask" defined as > > sea_binary_mask X_binary_mask has 1 where condition X is met, 0 > elsewhere. 1 = sea, 0 = land. > > This is used by the popular ROMS ocean model, and perhaps others. > > The new "sea_binary_mask" would join the existing "land_binary_mask", > which has 1 = land, 0 = sea. > > which makes it completely redundant. How hard it is to translate a > sea_binary_mask into a land_binary mask? > > as an end user, now all my code has to look for both, despite them being > the > same thing. > > Isn't it an ideal to have only one standard way to express a given > quantity? > > -Chris > > > > > > -- > Christopher Barker, Ph.D. > Oceanographer > > Emergency Response Division > NOAA/NOS/OR&R (206) 526-6959 voice > 7600 Sand Point Way NE (206) 526-6329 fax > Seattle, WA 98115 (206) 526-6317 main reception > > [email protected] > > > > -- Dr. Richard P. Signell (508) 457-2229 USGS, 384 Woods Hole Rd. Woods Hole, MA 02543-1598 _______________________________________________ CF-metadata mailing list [email protected] http://mailman.cgd.ucar.edu/mailman/listinfo/cf-metadata
