John raises some good points, which I think are apropos of the fact that
a set of terms for area_type will probably have to be more comprehensive
than what are currently in use in CF for cell_methods use. Maybe I'm
assuming that this was the original idea behind the list (for cell
methods),
because that's what ticket 17 is about.
It seems like it's worth it to try to create a reasonably complete list
of area
types, though, if one doesn't exist already, since it could be useful in
different contexts (i.e. for observational data). It will probably be used
beyond the original intended purpose, in any case.
I'm also confused by one additional item that hasn't been mentioned yet.
Does the fact of the 'ice_free_sea' area type imply that plain 'sea'
has ice?
Or is 'sea' just a less definitive term that may or may not have ice? This
might be clear in cell methods use, but it would be confusing in more
general
uses of this kind of list.
Also, I could not find a discussion of the difference between
floating_ice and
sea_ice in ticket 17. If one of these terms excludes icebergs by common
usage
in the modeling community, I'm not aware of the convention.
Cheers - Nan
I have a few suggestions for the area_type info. Well, more like
questions.
An area_type that I imagine being useful within a year or two, if not
within months, is the benthic floor (i.e., land under the sea). And
by analog: land under a lake, or the more general
water_covered_ground. I'm not recommending those changes now, but they
raise the following question: Is 'land' is intended to be
all-encompassing in this regard? Definitions would help make this
clear. As a general observation, discussing terms without associated
definitions can lead to confusion on all parts.
I don't see how all_standard_names makes sense as an area_type.
If lake_ice_or_sea_ice excludes icebergs, does sea_ice? This is
counterintuitive to a lay person, admittedly not the target audience.
(Also note, this is where the relation between terms is useful
information to have -- somewhere in my assumed hierarchy
floating_ice
lake_ice_or_sea_ice
sea_ice
there is a discrepancy, perhaps intentional. Suggest the discontinuity
be made explicit in the definition (i..e, explain why
lake_ice_or_sea_ice excludes icebergs, while floating_ice does not;
and address whether sea_ice includes icebergs. The definition is
where people will look to understand the relationships.
I assume the absence of lake_ice is deliberate. (Just a thought:
Sometimes completeness is helpful for clarity, especially when there
are no definitions, even though there may not be any immediate use for
the term. Otherwise it makes some of us wonder why something *wasn't*
included.)
John
On Dec 4, 2008, at 6:03 AM, Pamment, JA (Alison) wrote:
Dear All,
Velimir and I have been working on creating the new table of
standardized area_type strings as agreed under trac ticket 17. The
table lists the values permitted in variables with a standard_name of
area_type. To view version 1 of the table please go to
http://cf-pcmdi.llnl.gov/documents/cf-standard-names/area-type-table/cur
rent/area-type-table. Clicking on the individual table entries will
reveal explanatory text, although currently there is only help available
for the two new floating_ice strings. Please let us know if you have
any comments about the format of the table.
For ease of reference, there is also now a link from the area_type
description text in the html version of the standard_name table to the
new area_type table.
At the top of the standard name table a link has been created to the
standard name Guidelines document. This has been done with the
intention of giving greater prominence on the website to the existence
of the Guidelines.
The html copy of the standard name table has been rebuilt to add the new
links, but this in no way affects the contents of the table which
remains at version 11. There are no changes to the xml version of the
table.
Velimir has converted the standard name Guidelines document to the
docbook format (similar to the conventions document) and this hopefully
will make it more navigable. In addition, we have introduced version
numbering of the Guidelines. This is in response to the fact that there
has been a number of recent changes to the document and it looks likely
that there will be more in the future. The Guidelines are currently at
version 1 and this number will be incremented each time a change is
made.
If you have any comments regarding any of the above, please send them to
the list.
Best wishes,
Alison
==> Please note new email address: [EMAIL PROTECTED] <==
--
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* Nan Galbraith (508) 289-2444 *
* Upper Ocean Processes Group Mail Stop 29 *
* Woods Hole Oceanographic Institution *
* Woods Hole, MA 02543 *
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