Hi Glenn-
On 2/29/12 8:40 AM, Glenn Rutledge wrote:
Touche Don. (or should I say Dave Bowman)
;-)
This is a difficult issue for me to decide upon b/c in a sense, we are
all right. Can we achieve a parsing of the long name to the short name
for client displays etc.
And vice-versa (lookup by long name). However, John has already said
that the long name is volatile so I'm not sure what relying on the long
name gets us.
John- care to chime in ?
On Wed, Feb 29, 2012 at 10:14 AM, Don Murray <don.murray@xxxxxxxx
<mailto:don.murray@xxxxxxxx>> wrote:
Hi Glenn-
Thanks for the response. What I hear you saying is that the
underlying infrastructure that John is creating (i.e. the
GribFeatureCollection) and the fixes to what's broken in the
identification of the data (e.g. the break out of the variables on
different accumlation times) will help you provide consistent
results. I agree that these changes are necessary.
However, I think the same thing can be achieved with the human
readable variable names. There is no guarantee that the VAR_* names
won't change in the future. As John discussed with me last week, if
he finds a new PDS variable that he thinks is important, it could be
added to the variable name and then we go through the pain again.
That's no different than changing the human readable names. The
lookup for creating consistent human readable names is already there
to create the long name.
Even with the human readable names, there will be pain for tool
developers that access the data, because some names will change. It
will require changes to the IDV, but at least they will be
manageable. The permalinks in the Godiva WMS viewer that is part of
the TDS will break because they use the variable name to get the data.
I think the human readable names serve the end users better than the
VAR_* names. For example, if I go to NOMADS now and go to a GRIB2
file and choose the OPeNDAP view, I get a list of variables that I
can choose. Ex:
http://nomads.ncdc.noaa.gov/__thredds/dodsC/gfs4/201202/__20120229/gfs_4_20120229_0000___180.grb2.html
<http://nomads.ncdc.noaa.gov/thredds/dodsC/gfs4/201202/20120229/gfs_4_20120229_0000_180.grb2.html>
The variables that are selectable are in bold letters and easy to
read. I can quickly scroll through the page to find the variable
I'm interested in. While the long_name is listed in lesser print, it
doesn't stand out like the variable name does. In the new scheme,
what will stand out on the page is lots of VAR_* names which all
look similar. You could argue that no one uses this OPeNDAP
interface, but I know that there are some who do.
Or, if I go to the NetcdfSubsetService for a grib file on motherlode:
http://motherlode.ucar.edu/__thredds/ncss/grid/fmrc/NCEP/__GFS/Global_onedeg/files/GFS___Global_onedeg_20120229_0600.__grib2/dataset.html
<http://motherlode.ucar.edu/thredds/ncss/grid/fmrc/NCEP/GFS/Global_onedeg/files/GFS_Global_onedeg_20120229_0600.grib2/dataset.html>
I see human readable names. In the end, I don't see that the VAR_
names serve the end user.
As someone on the IDV users list said, "Hal, who do you serve:
machines or humans?" ;-)
Don
On 2/29/12 7:16 AM, Glenn Rutledge wrote:
Hi Don,
That is a very good question and I left that out in my response.
Long term access for users in archives means we constantly have
to work
to fully document, understand, track down any data provenance
issues,
and verifying (to a lessor degree), the data. What it says it
is- it
actually is. Its just a form of quality assurance for users. Data
providers - especially 'real time' ones don't necessarily concern
themselves with these issues. They make a product- and move on.
I'll
bet you are fully aware that the WOC/Gateway does not even provide a
complete DTG in the file name for many NWP products! I used to
work w/
John Stackpole (great guy)- the original developer of Grib. He
made grib
as a compact communications protocol- not, as I'll also bet you
are also
aware, for archives.
NOMADS has about 1+ petabyte to manage for users- we serviced a
growing
550TB last year and we need to scale. By aggregating the data
most used
by users (common state variables, most popular, etc.) we can allow
streaming of files/records that allows the 50K+ users and ~300
million
downloads per year on NOMADS much better. Methods such as
pre-staging/caching most requested data on disk from tape, etc. etc.
What John is attempting to do will facilitate the access for
multiple
users, requesting multiple files using aggregations and other
streaming
caching (I don't quite understand the details there). Now- we
can't even
ascertain with any degree of confidence what is what- in order
to even
be able to aggregate- let alone feel comfortable about the
accuracy of
the data we are serving to users.
It does not really help users find data- per se. It will help users
have more confidence that a aggregated monthly mean product from
CFSR is
mean for each cycle (0, 6, 12, ..) for individual days of the
month (the
diurnals)- rather then a typical monthly mean avg'ed over the
entire day.
hope that makes sense. I'm not sure what other impacts this
will have
for us here - LAS? our TDS to ESGF capabilities? It's kinda
scary, but
John's radical change looks to solve a major archive problem I
do know
that. We will run 4.2 and 4.3 in parallel I will tell you that for
some time.
Best regards, Glenn
On Tue, Feb 28, 2012 at 2:19 PM, Don Murray <don.murray@xxxxxxxx
<mailto:don.murray@xxxxxxxx>
<mailto:don.murray@xxxxxxxx <mailto:don.murray@xxxxxxxx>>> wrote:
Hi Glenn-
On 2/28/12 11:43 AM, Glenn Rutledge wrote:
John and Community-
While I do not represent the NCDC Archive, for the NCDC
NOMADS
systems
and our users, I must agree that the changes John is
proposing will
facilitate the long term use of grib data. While painful to
(existing)
client (software | decoders), the proposed change will
allow our
users
(with a more scalable way) to -better find and use our
data. I'll
suggest that if this is adopted, NOMADS servers could
provide
both 4.2
and 4.3 versions to (give software developers time to adapt)
allow the
client-side to adapt.
Could you elaborate on how you see that the new variable
names will
allow the users to better find and use your data versus the
human
readable names? For example, if I want to get the 500 hPa
heights
from a model in your archive, how will the new names
facilitate that?
Don
--
Don Murray
NOAA/ESRL/PSD and CIRES
303-497-3596 <tel:303-497-3596> <tel:303-497-3596
<tel:303-497-3596>>
http://www.esrl.noaa.gov/psd/____people/don.murray/
<http://www.esrl.noaa.gov/psd/__people/don.murray/>
<http://www.esrl.noaa.gov/psd/__people/don.murray/
<http://www.esrl.noaa.gov/psd/people/don.murray/>>
--
Glenn K. Rutledge
Meteorologist/Physical Scientist
NOMADS Team Leader
National Climatic Data Center
Asheville, NC 28801
(828) 271-4097 <tel:%28828%29%20271-4097>
nomads.ncdc.noaa.gov <http://nomads.ncdc.noaa.gov>
<http://nomads.ncdc.noaa.gov>
--
Don Murray
NOAA/ESRL/PSD and CIRES
303-497-3596 <tel:303-497-3596>
http://www.esrl.noaa.gov/psd/__people/don.murray/
<http://www.esrl.noaa.gov/psd/people/don.murray/>
--
Glenn K. Rutledge
Meteorologist/Physical Scientist
NOMADS Team Leader
National Climatic Data Center
Asheville, NC 28801
(828) 271-4097 <tel:%28828%29%20271-4097>
nomads.ncdc.noaa.gov <http://nomads.ncdc.noaa.gov>
--
Don Murray
NOAA/ESRL/PSD and CIRES
303-497-3596
http://www.esrl.noaa.gov/psd/people/don.murray/
