Chris,
I see what you are saying about category, yet it is metric. Within the
domain of months and years (without days, leap days, etc), it is
completely possible to do exact math, just as we can within the domain
of seconds, minutes, hours, and days. The problem arises when you try to
I remember this coming up on this list a while back.
Yes, the concept of e.g. monthly averaged data is useful.
But in that case, a “month” is really a category, not a continuous time
variable.
So we need a different way if describing it than a time access with units
of month...
-CHB
Sent from
Dear All,
I'd like to reiterate what I pointed out yesterday.
The CDM and EDAL support all of what's being talked about here by accepting
that udunits coordinate time is one of three ways to handle date/time
coordinates. They also support a calendar-based coordinate that behaves much
like
I like how you have described the issue, Chris.
Using month in anything except a 360-day calendar (assuming the month is
defined correctly for that calendar) produces erroneous results if you
try to do anything but math that remains in those units - such as
convert a month count to a date.
Calendars are a mess— both because the earth’s rotation is not
human-frendly, and because of human legacy.
So we need to accept that, and not try to use calendars as though they
are logical units for time.
I like to think about it this way: there are time operations: “this
much time has passed”,
Dear Martin
I agree that snow is a specific form of ice, and that we have and need many
standard names which refer to it. I'm questioning only the need for the area
type of ice_on_land, because I'm wondering in which circumstances one needs to
consider the area occupied by all conceivable forms
Dear all,
I agree with Jonathan's wish for a more well-behaved Earth in the planetary
system :-)
However, awaiting this I think that we have two issues before us:
1. The fact that different datasets fundamentally are based on different length
of a year, while Udunits defines a year to be the
Dear Karl, Jonathan,
I appreciate where you are coming from with the assertions that snow is a form
of ice, but it ain't necessarily so, at least not in the current CF names list.
Karl has made the point that there are multiple issues to consider when
comparing usage in area types with usage
