Hi Steve,
As I understand, without bounds, strictly speaking, the data is
regularly spaced point data. So, should it really belong to discrete
sampling geometries since "Discrete sampling geometry datasets are
characterized by a dimensionality that is lower than that of the
space-time region that is sampled"? If yes, featureType could possibly
be used to resolve the ambiguity. Just my two cents.
Upendra
On 8/11/2011 12:33 PM, Steve Hankin wrote:
On 8/11/2011 9:14 AM, Upendra Dadi wrote:
Hi,
I have a related question about "bounds" attribute. I often see
regularly gridded latitude-longitude data which do not have "bounds"
specified when probably they should. But they almost always have
regularly spaced latitude and longitude values which are at the
middle of each cell. CF checkers have no way to identify the problem
since files are valid both ways even though CF implementations might
interpret them differently (do they?). My question is what are the
consequences of not having "bounds" for analysis operations that are
commonly used in various models.
Hi Upendra,
The introduction to CF Chapter 4 states:
"If bounds are not provided, an application might reasonably
assume the gridpoints to be at the centers of the cells, but we do
not require that in this standard. "
Arguably this could/should be tightened up to say "If bounds are not
provided, applications should assume the gridpoints to be at the
centers of the cells. " in order to remove any ambiguity. Opinions
whether there might be any backwards compatibility issues from this
change?
- Steve
Upendra
On 8/10/2011 8:31 AM, John Caron wrote:
On 8/8/2011 3:43 PM, Jim Biard wrote:
Hi.
I have a time series of monthly averaged values. I have an
integer-valued time coordinate variable and an associated
time_bounds variable. Is it correct to use the 15th of February
and the 16th of all the other months for my time centers, or should
I use the 16th of every month?
Also, should I do anything differently if my data are
climatological monthly averages (say, over 30 years of data)? And,
in this case, should the time coordinate values be day numbers from
the beginning of the 30-year time interval, the end of the time
interval, or something else entirely?
Grace and peace,
Jim Biard
At the moment, IMO the best that can be done in CF is to accurately
record the date range (using the bounds attribute). The coordinate
value should then be considered for labeling purposes only. Make a
one line description and put into the long_name attribute. Make sure
you have human readable documentation that explains whats going on
in detail, and add a global attribute that references it. Set up a
24-hour hotline to answer questions, staffed by post-docs wearing
beepers. Ok, maybe not the last ;^)
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