[Esip-documentation] Let's get rid of spatial and temporal bounds in ACDD

[Armstrong, Edward M (398M)]

I would rather keep the onus on tools developers to properly update these attributes.  Our subsetting tools at the PO.DAAC do (L2 subsetting, not sure about LAS) do update.  The attributes themselves have tremendous value before the subsetting stage.

For one, they are very human readable. And for L2 data the elegantly set the bounds….something you have to be a little clever about if you work with just coord variables.


On Mar 7, 2014, at 10:19 AM, David Neufeld - NOAA Affiliate <david.neufeld at noaa.gov<mailto:david.neufeld at noaa.gov>> wrote:

Second!  I've seen this issue enough times to recognize that the benefit of a human configured/readable attribute is outweighed by the maintenance and generally error prone nature of this approach (aka copy paste mistakes).

-Dave


On Fri, Mar 7, 2014 at 11:09 AM, Signell, Richard <rsignell at usgs.gov<mailto:rsignell at usgs.gov>> wrote:
Gang,
I was just burned by gespatial and temporal bounds in ACDD again, and
it took us a while to find, so I'm irritated enough to get up from my
Friday afternoon office nap and write this message.  ;-)

The problem is that as soon as someone subsets or aggregates data from
netcdf or opendap datasets that use ACDD, the ACDD attributes in the
resulting dataset are wrong.   Since we subset and aggregate data all
the time, the ACDD metadata is often wrong.   The only way to correct
this would be to ensure that *all* clients that subset or aggregate
NetCDF or OpenDAP data modify the ACDD attributes in the output
datasets.   Yeah, right! ;-)

Since we already have CF compliant data, we have the information to
calculate the bounds from the coordinate variables.  So the temporal
and geospatial bounds can be accurately calculated by tools like
ncISO, which generates ISO metadata.   And if we subset or aggregate
the data and serve *that* up, ncISO will still generate the proper
bounds.

So I propose we stop saying that these properties at:
http://wiki.esipfed.org/index.php/Attribute_Convention_for_Data_Discovery_1-1
are "Recommended" and start saying "Not Recommended" for all
attributes that involve coordinate variables:

geospatial_bounds
geospatial_lat_min
geospatial_lat_max
geospatial_lon_min
geospatial_lon_max
geospatial_vertical_min
geospatial_vertical_max
time_coverage_start
time_coverage_stop
time_coverage_duration
time_coverage_resolution

Do I have a second?   :-)

-Rich
--
Dr. Richard P. Signell   (508) 457-2229<tel:%28508%29%20457-2229>
USGS, 384 Woods Hole Rd.
Woods Hole, MA 02543-1598
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-ed

Ed Armstrong
JPL Physical Oceanography DAAC
818 519-7607



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