Nice, thanks, Jim.
My only suggestion, after a very quick read-through, is that we could
put the definition of platform at the end of the variable's definition.
That makes it much easier to scan these for the right term.
Cheers - Nan
Quoting Jim Biard <jbi...@cicsnc.org>:
Hi.
How about these definitions?
Jim
==================
platform_roll_starboard_down: Platform is a structure or vehicle
that serves as a base for mounting sensors. Platforms include, but
are not limited to, satellites, aeroplanes, ships, buoys, ground
stations, and masts. Roll is a rotation about an axis that is
perpendicular to the local vertical axis and is coplanar with the
nominal forward motion direction of the platform. Roll is relative
to the ?at rest? rotation of the platform with respect to the axis
of rotation. The ?at rest? rotation of the platform may change over
time. "Starboard down" indicates that positive values of roll
represent the right side of the platform falling as viewed by an
observer on top of the platform facing forward.
platform_roll_starboard_up: Platform is a structure or vehicle that
serves as a base for mounting sensors. Platforms include, but are
not limited to, satellites, aeroplanes, ships, buoys, ground
stations, and masts. Roll is a rotation about an axis that is
perpendicular to the local vertical axis and is coplanar with the
nominal forward motion direction of the platform. Roll is relative
to the ?at rest? rotation of the platform with respect to the axis
of rotation. The ?at rest? rotation of the platform may change over
time. "Starboard up" indicates that positive values of roll
represent the right side of the platform rising as viewed by an
observer on top of the platform facing forward.
platform_roll_rate_starboard_down: Platform is a structure or
vehicle that serves as a base for mounting sensors. Platforms
include, but are not limited to, satellites, aeroplanes, ships,
buoys, ground stations, and masts. "Roll rate" is the rate of
rotation about an axis that is perpendicular to the local vertical
axis and is coplanar with the nominal forward motion direction of
the platform. Roll rate might not include changes to the ?at rest?
rotation of the platform with respect to the axis of rotation, which
may change over time. "Starboard down" indicates that positive
values of roll rate represent the right side of the platform falling
as viewed by an observer on top of the platform facing forward.
platform_roll_rate_starboard_up: Platform is a structure or vehicle
that serves as a base for mounting sensors. Platforms include, but
are not limited to, satellites, aeroplanes, ships, buoys, ground
stations, and masts. "Roll rate" is the rate of rotation about an
axis that is perpendicular to the local vertical axis and is
coplanar with the nominal forward motion direction of the platform.
Roll rate might not include changes to the ?at rest? rotation of the
platform with respect to the axis of rotation, which may change over
time. "Starboard up" indicates that positive values of roll rate
represent the right side of the platform rising as viewed by an
observer on top of the platform facing forward.
platform_pitch_fore_up: Platform is a structure or vehicle that
serves as a base for mounting sensors. Platforms include, but are
not limited to, satellites, aeroplanes, ships, buoys, ground
stations, and masts. Pitch is a rotation about an axis that is
perpendicular to both the local vertical axis and the nominal
forward motion direction of the platform. Pitch is relative to the
?at rest? rotation of the platform with respect to the axis of
rotation. The ?at rest? rotation of the platform may change over
time. "Fore up" indicates that positive values of pitch represent
the front of the platform rising as viewed by an observer on top of
the platform facing forward.
platform_pitch_fore_down: Platform is a structure or vehicle that
serves as a base for mounting sensors. Platforms include, but are
not limited to, satellites, aeroplanes, ships, buoys, ground
stations, and masts. Pitch is a rotation about an axis that is
perpendicular to both the local vertical axis and the nominal
forward motion direction of the platform. Pitch is relative to the
?at rest? rotation of the platform with respect to the axis of
rotation. The ?at rest? rotation of the platform may change over
time. "Fore down" indicates that positive values of pitch represent
the front of the platform falling as viewed by an observer on top of
the platform facing forward.
platform_pitch_rate_fore_up: Platform is a structure or vehicle that
serves as a base for mounting sensors. Platforms include, but are
not limited to, satellites, aeroplanes, ships, buoys, ground
stations, and masts. "Pitch rate" is the rate of rotation about an
axis that is perpendicular to both the local vertical axis and the
nominal forward motion direction of the platform. Pitch rate might
not include changes to the ?at rest? rotation of the platform with
respect to the axis of rotation, which may change over time. "Fore
up" indicates that positive values of pitch rate represent the front
of the platform rising as viewed by an observer on top of the
platform facing forward.
platform_pitch_rate_fore_down: Platform is a structure or vehicle
that serves as a base for mounting sensors. Platforms include, but
are not limited to, satellites, aeroplanes, ships, buoys, ground
stations, and masts. "Pitch rate" is the rate of rotation about an
axis that is perpendicular to both the local vertical axis and the
nominal forward motion direction of the platform. Pitch rate might
not include changes to the ?at rest? rotation of the platform with
respect to the axis of rotation, which may change over time. "Fore
down" indicates that positive values of pitch rate represent the
front of the platform falling as viewed by an observer on top of the
platform facing forward.
platform_yaw_fore_starboard: Platform is a structure or vehicle that
serves as a base for mounting sensors. Platforms include, but are
not limited to, satellites, aeroplanes, ships, buoys, ground
stations, and masts. Yaw is a rotation about the axis of rotation.
Yaw is relative to the ?at rest? rotation of the platform with
respect to the axis of rotation. The ?at rest? rotation of the
platform may change over time. "Fore starboard" indicates that
positive values of yaw represent the front of the platform moving to
the right as viewed by an observer on top of the platform facing
forward.
platform_yaw_fore_port: Platform is a structure or vehicle that
serves as a base for mounting sensors. Platforms include, but are
not limited to, satellites, aeroplanes, ships, buoys, ground
stations, and masts. Yaw is a rotation about the axis of rotation.
Yaw is relative to the ?at rest? rotation of the platform with
respect to the axis of rotation. The ?at rest? rotation of the
platform may change over time. "Fore port" indicates that positive
values of yaw represent the front of the platform moving to the left
as viewed by an observer on top of the platform facing forward.
platform_yaw_rate_fore_starboard: Platform is a structure or vehicle
that serves as a base for mounting sensors. Platforms include, but
are not limited to, satellites, aeroplanes, ships, buoys, ground
stations, and masts. "Yaw rate" is the rate of rotation about the
axis of rotation. Yaw rate might not include changes to the ?at
rest? rotation of the platform with respect to the axis of rotation,
which may change over time. "Fore starboard" indicates that positive
values of yaw rate represent the front of the platform moving to the
right as viewed by an observer on top of the platform facing forward.
platform_yaw_rate_fore_port: Platform is a structure or vehicle that
serves as a base for mounting sensors. Platforms include, but are
not limited to, satellites, aeroplanes, ships, buoys, ground
stations, and masts. "Yaw rate" is the rate of rotation about the
axis of rotation. Yaw rate might not include changes to the ?at
rest? rotation of the platform with respect to the axis of rotation,
which may change over time. "Fore port" indicates that positive
values of yaw rate represent the front of the platform moving to the
left as viewed by an observer on top of the platform facing forward.
platform_surge_fore: Platform is a structure or vehicle that serves
as a base for mounting sensors. Platforms include, but are not
limited to, satellites, aeroplanes, ships, buoys, ground stations,
and masts. Surge is a displacement along an axis that is
perpendicular to the local vertical axis and is coplanar with the
nominal forward motion direction of the platform. Surge is relative
to the ?at rest? position of the platform with respect to the axis
of displacement. The ?at rest? position of the platform may change
over time. "Fore" indicates that positive values of surge represent
the platform moving forward as viewed by an observer on top of the
platform facing forward.
platform_surge_aft: Platform is a structure or vehicle that serves
as a base for mounting sensors. Platforms include, but are not
limited to, satellites, aeroplanes, ships, buoys, ground stations,
and masts. Surge is a displacement along an axis that is
perpendicular to the local vertical axis and is coplanar with the
nominal forward motion direction of the platform. Surge is relative
to the ?at rest? position of the platform with respect to the axis
of displacement. The ?at rest? position of the platform may change
over time. "Aft" indicates that positive values of surge represent
the platform moving backward as viewed by an observer on top of the
platform facing forward.
platform_surge_rate_fore: Platform is a structure or vehicle that
serves as a base for mounting sensors. Platforms include, but are
not limited to, satellites, aeroplanes, ships, buoys, ground
stations, and masts. "Surge rate" is the rate of displacement along
an axis that is perpendicular to the local vertical axis and is
coplanar with the nominal forward motion direction of the platform.
Surge rate might not include changes to the ?at rest? position of
the platform with respect to the axis of displacement, which may
change over time. "Fore" indicates that positive values of surge
rate represent the platform moving forward as viewed by an observer
on top of the platform facing forward.
platform_surge_rate_aft: Platform is a structure or vehicle that
serves as a base for mounting sensors. Platforms include, but are
not limited to, satellites, aeroplanes, ships, buoys, ground
stations, and masts. "Surge rate" is the rate of displacement along
an axis that is perpendicular to the local vertical axis and is
coplanar with the nominal forward motion direction of the platform.
Surge rate might not include changes to the ?at rest? position of
the platform with respect to the axis of displacement, which may
change over time. "Aft" indicates that positive values of surge rate
represent the platform moving backward as viewed by an observer on
top of the platform facing forward.
platform_sway_port: Platform is a structure or vehicle that serves
as a base for mounting sensors. Platforms include, but are not
limited to, satellites, aeroplanes, ships, buoys, ground stations,
and masts. Sway is a displacement along an axis that is
perpendicular to both the local vertical axis and the nominal
forward motion direction of the platform. Sway is relative to the
?at rest? position of the platform with respect to the axis of
displacement. The ?at rest? position of the platform may change over
time. "Port" indicates that positive values of sway represent the
platform moving left as viewed by an observer on top of the platform
facing forward.
platform_sway_starboard: Platform is a structure or vehicle that
serves as a base for mounting sensors. Platforms include, but are
not limited to, satellites, aeroplanes, ships, buoys, ground
stations, and masts. Sway is a displacement along an axis that is
perpendicular to both the local vertical axis and the nominal
forward motion direction of the platform. Sway is relative to the
?at rest? position of the platform with respect to the axis of
displacement. The ?at rest? position of the platform may change over
time. "Starboard" indicates that positive values of sway represent
the platform moving right as viewed by an observer on top of the
platform facing forward.
platform_sway_rate_port: Platform is a structure or vehicle that
serves as a base for mounting sensors. Platforms include, but are
not limited to, satellites, aeroplanes, ships, buoys, ground
stations, and masts. "Sway rate" is the rate of displacement along
an axis that is perpendicular to both the local vertical axis and
the nominal forward motion direction of the platform. Sway rate may
not include changes to the ?at rest? position of the platform with
respect to the axis of displacement, which may change over time.
"Port" indicates that positive values of sway rate represent the
platform moving left as viewed by an observer on top of the platform
facing forward.
platform_sway_rate_starboard: Platform is a structure or vehicle
that serves as a base for mounting sensors. Platforms include, but
are not limited to, satellites, aeroplanes, ships, buoys, ground
stations, and masts. "Sway rate" is a displacement along an axis
that is perpendicular to both the local vertical axis and the
nominal forward motion direction of the platform. Sway rate may not
include changes to the ?at rest? position of the platform with
respect to the axis of displacement, which may change over time.
"Starboard" indicates that positive values of sway rate represent
the platform moving right as viewed by an observer on top of the
platform facing forward.
platform_heave_up: Platform is a structure or vehicle that serves as
a base for mounting sensors. Platforms include, but are not limited
to, satellites, aeroplanes, ships, buoys, ground stations, and
masts. Heave is a displacement along the local vertical axis. Heave
is relative to the ?at rest? position of the platform with respect
to the axis of displacement. The ?at rest? position of the platform
may change over time. "Up" indicates that positive values of heave
represent the platform moving up as viewed by an observer on top of
the platform facing forward.
platform_heave_down: Platform is a structure or vehicle that serves
as a base for mounting sensors. Platforms include, but are not
limited to, satellites, aeroplanes, ships, buoys, ground stations,
and masts. Heave is a displacement along the local vertical axis.
Heave is relative to the ?at rest? position of the platform with
respect to the axis of displacement. The ?at rest? position of the
platform may change over time. "Down" indicates that positive values
of heave represent the platform moving down as viewed by an observer
on top of the platform facing forward.
platform_heave_rate_up: Platform is a structure or vehicle that
serves as a base for mounting sensors. Platforms include, but are
not limited to, satellites, aeroplanes, ships, buoys, ground
stations, and masts. "Heave rate" is the rate of displacement along
the local vertical axis. Heave rate may not include changes to the
?at rest? position of the platform with respect to the axis of
displacement, which may change over time. "Up" indicates that
positive values of heave rate represent the platform moving up as
viewed by an observer on top of the platform facing forward.
platform_heave_rate_down: Platform is a structure or vehicle that
serves as a base for mounting sensors. Platforms include, but are
not limited to, satellites, aeroplanes, ships, buoys, ground
stations, and masts. "Heave rate" is the rate of displacement along
the local vertical axis. Heave rate may not include changes to the
?at rest? position of the platform with respect to the axis of
displacement, which may change over time. "Down" indicates that
positive values of heave rate represent the platform moving down as
viewed by an observer on top of the platform facing forward.
platform_course: Platform is a structure or vehicle that serves as a
base for mounting sensors. Platforms include, but are not limited
to, satellites, aeroplanes, ships, buoys, ground stations, and
masts. Course is the clockwise angle with respect to North of the
nominal forward motion direction of the platform.
platform_orientation: Platform is a structure or vehicle that serves
as a base for mounting sensors. Platforms include, but are not
limited to, satellites, aeroplanes, ships, buoys, ground stations,
and masts. Orientation is the clockwise angle with respect to North
of the longitudinal (front-to-back) axis of the platform, which may
be different than the platform course (see platform_course).
On 9/11/18 12:13 PM, Lowry, Roy K. wrote:
Dear Nan and Jim,
It was me, on my own volition, who raised concerns about the use of
nautical terms to try and make the concepts domain-independent.
However, 'port' is such an elegant way of saying 'left when facing
forward' that I don't think we should resist it. Saw a nice
definition for port - 'The side of a platform that is on the left
when one is facing forward.'
Cheers, Roy.
I have now retired but will continue to be active through an
Emeritus Fellowship using this e-mail address.
------------------------------------------------------------------------
*From:* CF-metadata <cf-metadata-boun...@cgd.ucar.edu> on behalf of
Jim Biard <jbi...@cicsnc.org>
*Sent:* 11 September 2018 16:37
*To:* cf-metadata@cgd.ucar.edu
*Subject:* Re: [CF-metadata] Platform Heave
Nan,
That was my concern. As I have thought about it, we can make it
clear in the definition text. I'll generate those later this week.
Jim
On 9/11/18 10:53 AM, Nan Galbraith wrote:
I agree completely. Thanks to all for keeping at it with this topic.
* platform_roll_starboard_down
* platform_yaw_fore_starboard
* platform_pitch_fore_up
* platform_surge_fore
* platform_sway _port
* platform_heave_up
There was some concern expressed about using port and starboard, because
satellite folks don't normally use those terms. I was unable to
figure out exactly
who raised this point, the thread is long and sometimes my mail
client makes the
sender of each message a little obscure.
I'm assuming even satellites have a 'front' - ADCPs don't, really,
except by some
obscure convention set by the vendors - so presumably people will
be able to figure
out which side is which, and these terms will be OK.
- Nan
On 9/7/18 4:07 AM, Lowry, Roy K. wrote:
Good point,
So you'd prefer platform_roll_starboard_down and so on?
Cheers, Roy.
------------------------------------------------------------------------
*From:* John Graybeal <jbgrayb...@mindspring.com>
<mailto:jbgrayb...@mindspring.com>
*Sent:* 07 September 2018 03:29
*Subject:* Re: [CF-metadata] Platform Heave
Sorry if I missed a point, but joining the motion to platform_
will be much more findable. Platform roll for example is a really
common expression.
John
On Sep 6, 2018, at 08:22, Lowry, Roy K. <r...@bodc.ac.uk
<mailto:r...@bodc.ac.uk> <mailto:r...@bodc.ac.uk>
<mailto:r...@bodc.ac.uk>> wrote:
Dear Jim,
Looking good to me.
Cheers, Roy.
------------------------------------------------------------------------
*From:* CF-metadata <cf-metadata-boun...@cgd.ucar.edu
<mailto:cf-metadata-boun...@cgd.ucar.edu>
<mailto:cf-metadata-boun...@cgd.ucar.edu>
<mailto:cf-metadata-boun...@cgd.ucar.edu>> on behalf of Jim
Biard <jbi...@cicsnc.org <mailto:jbi...@cicsnc.org>
<mailto:jbi...@cicsnc.org> <mailto:jbi...@cicsnc.org>>
*Sent:* 05 September 2018 17:38
*Subject:* Re: [CF-metadata] Platform Heave
Roy, Jonathan,
I expect that surge, sway, and heave may well not have any
"alternate direction" representations in the wild, but I recall
that we found that the same is not true of pitch, roll, and yaw.
Should we define the "canonical" set in such a fashion that the
sign convention is explicit and wait for people to request the
others?
I guess that would be:
* platform_starboard_down_roll
* platform_fore_starboard_yaw
* platform_fore_up_pitch
* platform_fore_surge
* platform_port_sway
* platform_up_heave
Is that what we want?
Grace and peace,
Jim
On 9/5/18 12:10 PM, Jonathan Gregory wrote:
Dear Roy OK, yes. I agree with that too! We should not provide
standard names for there is no use case yet. However, it's a
good idea for foresee how this may be done, so that a neat
solution is readily available when the day comes. Best wishes
and thanks Jonathan On Wed, Sep 05, 2018 at 04:07:26PM +0000,
Lowry, Roy K. wrote:
Date: Wed, 5 Sep 2018 16:07:26 +0000 From: "Lowry, Roy K."
<r...@bodc.ac.uk> <mailto:r...@bodc.ac.uk>
<mailto:r...@bodc.ac.uk> <mailto:r...@bodc.ac.uk> Subject: Re:
[CF-metadata] Platform Heave Dear Jonathan, This isn't a
desire to mandate, it's just an attempt to prevent the
creation of six unnecessary Standard Names for sign
conventions based on my knowledge and researches of
oceanographic data that don't exist. Should anybody come up
with a single example of the opposite sign convention in
heave/sway/surge from any other domain then the additional
Standard Names will obviously need setting up. Anybody know of
any??? It also goes without saying the 'normal' conventions
should leave the door open - for example 'upward heave' leaves
the door open for a future 'downward heave'. This follows
another principle of CF Standard Names which is that Standard
Names should only set up when there is a demonstrable use case
and not just in case a use case arises. Cheers, Roy. From:
CF-metadata <cf-metadata-boun...@cgd.ucar.edu>
<mailto:cf-metadata-boun...@cgd.ucar.edu>
<mailto:cf-metadata-boun...@cgd.ucar.edu>
<mailto:cf-metadata-boun...@cgd.ucar.edu> on behalf of
Jonathan Gregory <j.m.greg...@reading.ac.uk>
<mailto:j.m.greg...@reading.ac.uk>
<mailto:j.m.greg...@reading.ac.uk>
<mailto:j.m.greg...@reading.ac.uk> Sent: 05 September 2018 16:26
Subject: Re: [CF-metadata] Platform Heave Dear Jim and Roy In
general, we want CF to be able to describe the datasets that
users want to describe, rather than mandating particular
choices. Projects that use CF can do that, of course, like
CMIP6 does, which prescribes the standard_names of the
quantities to be submitted. Best wishes Jonathan
Date: Wed, 5 Sep 2018 09:32:37 -0400 From: Jim Biard
<jbi...@cicsnc.org> <mailto:jbi...@cicsnc.org>
<mailto:jbi...@cicsnc.org> <mailto:jbi...@cicsnc.org>
Subject: Re: [CF-metadata] Platform Heave
Roy, Good point! However (of course there has to be a
'but'!), are we OK with forcing people to modify their data
to match our convention? Are there other situations where a
standard name requires a certain representation? The existing
datasets that people have mentioned are history, but they are
also indicative of different sign conventions out there "in
the wild". Grace and peace, Jim On 9/5/18 4:22 AM, Lowry, Roy
K. wrote:
Dear Jim, I think maybe you're doing more work than
necessary. I see the work falling into three parts. 1)
Revision of the definitions of heave/heave rate that are
part of a new Standard Name that has yet to be accepted. 2)
Creation of new Standard Names for Ken for sway/sway rate
and surge/surge rate 3) Upgrade to the definitions of the
existing Standard Names for pitch, roll and yaw. How about
hard-wiring direction conventions for cases (1) and (2) -
heave positive up, surge positive forwards and sway to match
Ken's data sets? As these are new Standard Names they cannot
be out in the wild with the opposite direction convention.
We would then need to deprecate the three existing Standard
Names and replace them with six new ones. One other thought
that is occupying my mind is whether the rate parameters are
scalars or vectors? Any thoughts? Cheers, Roy. *From:*
CF-metadata <cf-metadata-boun...@cgd.ucar.edu>
<mailto:cf-metadata-boun...@cgd.ucar.edu>
<mailto:cf-metadata-boun...@cgd.ucar.edu>
<mailto:cf-metadata-boun...@cgd.ucar.edu> on behalf of Jim
Biard <jbi...@cicsnc.org> <mailto:jbi...@cicsnc.org>
<mailto:jbi...@cicsnc.org> <mailto:jbi...@cicsnc.org>
*Sent:* 04 September 2018 16:36 *Subject:* Re: [CF-metadata]
Platform Heave Jonathan, Two out of three of Nan's "most
intuitive" rotations (pitch and yaw) are clockwise rather
than anticlockwise if the unit vectors are X-fore, Y-port,
and Z-up, which form a right-hand coordinate system. This is
part of why you will see examples where the unit vectors are
defined as X-fore, Y-starboard, and Z-down. This orientation
of the unit vectors makes yaw to starboard, pitch up, and
roll starboard down all anticlockwise rotations, but it
points the Z unit vector down, which is, for most people,
rather counter-intuitive. And this is why we are trying to
define things in terms that don't require specification of
unit vector directions. I'm going to try to continue down
that path and avoid calling out clockwise/anticlockwise.
Grace and peace, Jim On 9/4/18 10:18 AM, Jonathan Gregory
wrote:
Dear Jim
If that's the general consensus, then we can go that
general direction. I'll prepare pairs of everything.
Thank you for your flexibility.
Regarding Nan's suggestions for names - I'm not a "ship
person" so starboard and port are unfamiliar terms that I
have to constantly check myself on. I dislike putting them
in the names. I don't see them in regular use in the
satellite domain. The same goes for bow as far as usage
outside of the ship domain. Airplanes have noses.
Satellites have ... I don't know if there is even a name,
as there is no need for a leading edge. I'll struggle to
find something, and then we can wrangle over it.
I agree with you - it would be better to have something
generic and self- explanatory, even if it diverges from
familiar terminology.
I think the "most intuitive" way to represent the angles -
and most consistent as well, in my view - is clockwise
rotations around the unit vectors. This makes positive yaw
to starboard, positive pitch nose up, and positive roll
starboard up. But we are talking about having both signs
represented in names, so I guess that is moot.
I agree with this too. For describing polygonal bounds, we
say that the vertices should be traversed anticlockwise as
seen from above. That is a positive direction of rotation
around the vertical axis, since longitude- latitude-upward
is a right-handed coordinate system. I suppose this is the
yaw rotation - but is that the opposite sign from yours?
Best wishes Jonathan
On 9/3/18 12:51 PM, Jonathan Gregory wrote:
Dear Roy and Nan I agree that if there are existing names
whose sign convention is undefined we can't
retrospectively define it. I think those ones ought to be
deprecated, though, in favour of new ones with signs
indicated. Best wishes Jonathan ----- Forwarded message
from Nan Galbraith<ngalbra...@whoi.edu>
<mailto:ngalbra...@whoi.edu> <mailto:ngalbra...@whoi.edu>
<mailto:ngalbra...@whoi.edu>-----
Date: Sun, 02 Sep 2018 11:57:33 -0400
From: Nan Galbraith<ngalbra...@whoi.edu>
<mailto:ngalbra...@whoi.edu> <mailto:ngalbra...@whoi.edu>
<mailto:ngalbra...@whoi.edu>
I second Roy's suggestion; existing names have
undefined directionality, and new names have explicit
directions. This seems like the only way to move
forward. If there's a difference of opinion on which
direction should be in the new name, we can easily
create a pair for each term. What would the explicit
names be? Some of the terms in the thread below use
'right' and 'left' where 'port' and 'starboard' might be
more clear, since, as Roy points out, left and right can
be taken as 'looking forwards from the platform or
looking at the front of the platform.' I also agree that
these are the most intuitive way to represent these
angles/motions:
heave positive up pitch positive bow up yaw positive to
starboard roll positive starboard side down
Would the names be something like heave_up,
pitch_bow_up, yaw_to_starboard, and roll_to_starboard?
We do need to differentiate these from the exiting
names. Regards - Nan Quoting "Lowry, Roy
K."<r...@bodc.ac.uk> <mailto:r...@bodc.ac.uk>
<mailto:r...@bodc.ac.uk> <mailto:r...@bodc.ac.uk>
<mailto:r...@bodc.ac.uk> <mailto:r...@bodc.ac.uk>
<mailto:r...@bodc.ac.uk> <mailto:r...@bodc.ac.uk>:
Dear Jim, From my researches into existing
oceanographic data sets (SeaDataCloud holdings plus EU
glider data projects), covering heave, pitch, roll and
yaw. I haven't discovered a single deviation from the
conventions:
heave positive up Pitch positive bow/nose up yaw
positive to starboard roll starboard side down I have
yet to find any data sets, other than those described
by Ken in these discussions, in my searches containing
surge or sway. The only ambiguity I have found in the
wider domain of Google is where the concept of
'positive clockwise' has been used without specifying
whether the observer is looking forwards from the
platform or looking at the front of the platform. This
isn't helped by the multitude of bidirectional vectors
(arrows at each end) in illustrative diagrams. Might
our lives be made easier if we adopted a set of
conventions, state them explicitly in the Standard
Names as Jonathan suggests leaving room in the unlikely
- in my view at least - event of Standard Names for the
opposite convention being required? Cheers, Roy. From:
CF-metadata on behalf of Jim Biard<jbi...@cicsnc.org>
<mailto:jbi...@cicsnc.org> <mailto:jbi...@cicsnc.org>
<mailto:jbi...@cicsnc.org>
Sent: 31 August 2018 14:38 Jonathan, That's only part
of the issue. Here are the issues as I see them. *
There is no single sign convention being followed in
existing datasets "in the wild". * There is a
long-standing convention for vertical coordinates using
the attribute positive rather than having pairs of
standard names for height_positive_up,
height_positive_down, etc. The suggested solution is
corollary, and the positive attribute could be used
instead of adding a new attribute named direction with
a suitable expansion of possible valid values. * In
order to cover all bases, we'd need three versions for
each standard name (e.g. - platform_roll,
platform_roll_clockwise, platform_roll_anticlockwise -
or similar names) * Having three different versions of
each standard name will lead to new possibilities for
getting things wrong by picking the wrong version. *
Semantically, there is only one concept in each case.
If I am searching for roll variables and I have
multiple names that mean roll, I must expand my search
to include all variants. This is a small example, but
there are other examples of this problem that are
definitely not trivial and defeat one of the goals for
using standard names - being able to find like
quantities across datasets, particularly using
automated techniques rather than human eyes. Grace and
peace, Jim On 8/31/18 8:52 AM, Jonathan Gregory wrote:
Dear all I haven't been following this discussion, so
please excuse me if I've missed the point. I think you
are suggesting introducing a new attribute to indicate
the positive sense of various new quantities for
platform orientation - is that right? To do that would
not be consistent with other standard names, which
(where relevant) all have the positive sense indicate
in the standard name itself. That's why there are many
pairs of standard names for upward/downward, in
particular. The reason for doing this is to make it
impossible to name the quantity without indicating its
sign convention, whereas a separate attribute can be
omitted, and probably sometimes will. It also opens new
possibilities for getting things wrong, by putting
illegal values in it. Therefore I would argue for the
same approach here, both because I think it's less
error-prone, and for consistency with other CF standard
names. I'm sure the objection occurs to you that this
means more standard names. That's true, but it's only
twice as many, I believe, since each of the quantities
has only two possible senses.
Best wishes Jonathan
----- Forwarded message from Kenneth Kehoe
<kke...@ou.edu> <mailto:kke...@ou.edu>
<mailto:kke...@ou.edu> <mailto:kke...@ou.edu>
<mailto:kke...@ou.edu> <mailto:kke...@ou.edu>
<mailto:kke...@ou.edu> <mailto:kke...@ou.edu>
Date: Thu, 30 Aug 2018 12:05:44 -0600
From: Kenneth Kehoe<kke...@ou.edu>
<mailto:kke...@ou.edu> <mailto:kke...@ou.edu>
<mailto:kke...@ou.edu>
Subject: Re: [CF-metadata] Platform Heave
I think we should keep things simple as Ethan suggests
below. But since the proposed attribute "direction" is
defined as indicating the positive direction we don't
need to include the word positive. The terms would then
be: roll: "right_side_up" and "right_side_down" pitch:
"nose_up" and "nose_down" yaw: "nose_right" and
"nose_left" surge: "forward" and "backward" sway:
"left" and "right" heave: "up" and "down" It would be
nice to be more explicit in the netCDF file and require
less on the standard_name definition so I would suggest
we use the original proposed attribute name of
"positive_direction" with the above allowed values. Or
if we don't want to add a new attribute we could use
the existing "positive" attribute and expand its
allowed use. I've proposed this in the past and it was
decided to not expand the definition. I think the
concern for not expanding positive was the requirement
of only using that attribute on coordinate variables.
For the coordinate variable the only allowable values
are up and down. But for this use those values would
only be attached to a variable, not a coordinate
variable. Since we are creating an attribute to define
the positive direction I would like to add radial
definition of "toward" and "away". But I think we can
simplify this a bit further. If we define the point of
reference that is moving in the standard name then we
don't need to put the point of reference in the
positive (or direction or positive_direction)
attribute. For example the pitch standard_name would
indicate the location of reference of the nose. This
would then reduce the list of possible options to:
roll: "up" and "down" pitch: "up" and "down" yaw:
"right" and "left" surge: "forward" and "backward"
sway: "left" and "right" heave: "up" and "down" If we
could use the current attribute of "positive" that has
up and down already defined then we only need to to add
"right", "left", "forward", "backward", "toward",
"away". Easy! Ken On 2018-8-29 13:54, Ethan Davis
wrote: Hey Jim, How about removing one layer of
terminology by using your definitions for the allowed
values of "direction": roll: "positive_right_side_up"
and "positive_right_side_down". pitch:
"positive_nose_up" and "positive_nose_down". yaw:
"positive_nose_right" and "positive_nose_left". surge:
"positive_forward" and "positive_backward". sway:
"positive_left" and "positive_right". heave:
"positive_up" and "positive_down". Cheers, Ethan On
Wed, Aug 29, 2018 at 12:02 PM Jim Biard
<jbi...@cicsnc.org <mailto:jbi...@cicsnc.org>
<mailto:jbi...@cicsnc.org>
<mailto:jbi...@cicsnc.org>>wrote: John, There are a
variety of conventions for defining roll, pitch, and
yaw out there. This is why we are avoiding a specific
one. Others have searched existing datasets that are
using earlier versions of these standard names (or not
using standard names) and found that they don't all
follow the same convention. Ethan, We purposely aren't
answering that question directly because of the issue
above. I believe that I have consistently followed the
convention in which clockwise and anticlockwise are
rotational directions around a unit vector facing the
observer, where the X unit vector is in the nominally
forward direction, the Z axis is in the local up
direction, and the Y axis unit vector is "Z cross X",
which forms a right-handed coordinate system. The terms
are meaningful and accurate using that convention, but
the names could be "alpha" and "beta" or "dog" and
"cat" as long as they are used correctly. This whole
topic is fraught with competing conventions, so we are
attempting to avoid declaring that only one of them is
valid, with it's corresponding requirement that
everyone follow that one sign convention. In fact, we
could reword things to remove naming the axes X, Y, and
Z, and perhaps we should. I know of satellite platforms
that define their Y axis unit vector as pointing
forward and the Z axis unit vector as pointing down.
Thoughts? Grace and peace, Jim On 8/29/18 1:32 PM, John
Helly wrote: Perhaps one should refer to the discipline
of hydrostatics for help with this? This paper, pulled
from a quick search, has a diagram referencing the
platforms' frame of reference with respect to its
center of gravity. Sorry if this comment is retrograd...
J. On 8/29/18 10:09, Ethan Davis wrote: Hi Jim, all,
I'm a bit confused by the "clockwise" and
"anticlockwise". You mention the orientation of the
observer but not the location/orientation of the clock.
My assumptions (not sure why) for the clock: for roll,
the observer (who is facing forward) would be facing
the clock; for pitch, the observer would look right to
see the clock; and for yaw, the observer would look
down to see the clock. That works for your definitions
of pitch and yaw, but is backwards for roll. Does
"clockwise" add, in some way, another degree of freedom
to the definition? Does that degree of freedom need to
be nailed down in the definitions? Or other terms used
instead? I don't have any good suggestions other than
"positive" and "negative". Cheers, Ethan On Wed, Aug
29, 2018 at 9:03 AM Jim Biard<jbi...@cicsnc.org>
<mailto:jbi...@cicsnc.org> <mailto:jbi...@cicsnc.org>
<mailto:jbi...@cicsnc.org> wrote: Hi. I've finally
gotten back to this topic! The definitions below call
out an attribute named "direction" that is used to
specify the direction for positive values of the
different quantities. We may need to add a definition
for the attribute to the Conventions. The values and
meanings for the direction attribute are: roll:
"clockwise" for positive right side up and
"anticlockwise" for positive right side down. pitch:
"clockwise" for positive nose up and "anticlockwise"
for positive nose down. yaw: "clockwise" for positive
nose right and "anticlockwise" for positive nose left.
surge: "positive" for positive forward and "negative"
for positive backward. sway: "positive" for positive
left and "negative" for positive right. heave:
"positive" for positive up and "negative" for positive
down. And here are the standard name definitions:
platform_roll: Platform is a structure or vehicle that
serves as a base for mounting sensors. Platforms
include, but are not limited to, satellites,
aeroplanes, ships, buoys, ground stations, and masts.
Roll is a rotation about an axis (the X axis) that is
perpendicular to the local vertical axis (the Z axis)
and is coplanar with the nominal forward motion
direction of the platform. Roll is relative to the ?at
rest? rotation of the platform with respect to the X
axis. The ?at rest? rotation of the platform may change
over time. The direction for positive values of roll is
specified by an attribute named direction. The value of
the direction attribute is "clockwise" if positive
values of roll represent the right side of the platform
rising as viewed by an observer on top of the platform
facing forward. The value of the direction attribute is
"anticlockwise" if positive values of roll represent
the right side of the platform falling. The
directionality of roll values is unspecified if no
direction attribute is present. platform_pitch:
Platform is a structure or vehicle that serves as a
base for mounting sensors. Platforms include, but are
not limited to, satellites, aeroplanes, ships, buoys,
ground stations, and masts. Pitch is a rotation about
an axis (the Y axis) that is perpendicular to both the
local vertical axis (the Z axis) and the nominal
forward motion direction of the platform. Pitch is
relative to the ?at rest? rotation of the platform with
respect to the Y axis. The ?at rest? rotation of the
platform may change over time. The direction for
positive values of pitch is specified by an attribute
named direction. The value of the direction attribute
is "clockwise" if positive values of pitch represent
the front of the platform rising as viewed by an
observer on top of the platform facing forward. The
value of the direction attribute is "anticlockwise" if
positive values of pitch represent the front of the
platform falling. The directionality of pitch values is
unspecified if no direction attribute is present.
platform_yaw: Platform is a structure or vehicle that
serves as a base for mounting sensors. Platforms
include, but are not limited to, satellites,
aeroplanes, ships, buoys, ground stations, and masts.
Yaw is a rotation about the local vertical axis (the Z
axis). Yaw is relative to the ?at rest? rotation of the
platform with respect to the Z axis. The ?at rest?
rotation of the platform may change over time. The
direction for positive values of yaw is specified by an
attribute named direction. The value of the direction
attribute is "clockwise" if positive values of yaw
represent the front of the platform moving to the right
as viewed by an observer on top of the platform facing
forward. The value of the direction attribute is
"anticlockwise" if positive values of yaw represent the
front of the platform moving to the left. The
directionality of yaw values is unspecified if no
direction attribute is present. platform_surge:
Platform is a structure or vehicle that serves as a
base for mounting sensors. Platforms include, but are
not limited to, satellites, aeroplanes, ships, buoys,
ground stations, and masts. Surge is a displacement
along an axis (the X axis) that is perpendicular to the
local vertical axis (the Z axis) and is coplanar with
the nominal forward motion direction of the platform.
Surge is relative to the ?at rest? position of the
platform with respect to the X axis. The ?at rest?
position of the platform may change over time. The
direction for positive values of surge is specified by
an attribute named direction. The value of the
direction attribute is "positive" if positive values of
surge represent the platform moving forward as viewed
by an observer on top of the platform facing forward.
The value of the direction attribute is "negative" if
positive values of surge represent the platform moving
backward. The directionality of surge values is
unspecified if no direction attribute is present.
platform_sway: Platform is a structure or vehicle that
serves as a base for mounting sensors. Platforms
include, but are not limited to, satellites,
aeroplanes, ships, buoys, ground stations, and masts.
Sway is a displacement along an axis (the Y axis) that
is perpendicular to both the local vertical axis (the Z
axis) and the nominal forward motion direction of the
platform. Sway is relative to the ?at rest? position of
the platform with respect to the Y axis. The ?at rest?
position of the platform may change over time. The
direction for positive values of sway is specified by
an attribute named direction. The value of the
direction attribute is "positive" if positive values of
sway represent the platform moving left as viewed by an
observer on top of the platform facing forward. The
value of the direction attribute is "negative" if
positive values of sway represent the platform moving
right. The directionality of sway values is unspecified
if no direction attribute is present. platform_heave:
Platform is a structure or vehicle that serves as a
base for mounting sensors. Platforms include, but are
not limited to, satellites, aeroplanes, ships, buoys,
ground stations, and masts. Heave is a displacement
along the local vertical axis (the Z axis). Heave is
relative to the ?at rest? position of the platform with
respect to the Z axis. The ?at rest? position of the
platform may change over time. The direction for
positive values of heave is specified by an attribute
named direction. The value of the direction attribute
is "positive" if positive values of heave represent the
platform moving up as viewed by an observer on top of
the platform facing forward. The value of the direction
attribute is "negative" if positive values of heave
represent the platform moving down. The directionality
of heave values is unspecified if no direction
attribute is present. platform_course: Platform is a
structure or vehicle that serves as a base for mounting
sensors. Platforms include, but are not limited to,
satellites, aeroplanes, ships, buoys, ground stations,
and masts. Course is the clockwise angle with respect
to North of the nominal forward motion direction of the
platform. platform_orientation: Platform is a structure
or vehicle that serves as a base for mounting sensors.
Platforms include, but are not limited to, satellites,
aeroplanes, ships, buoys, ground stations, and masts.
Orientation is the clockwise angle with respect to
North of the longitudinal (front-to-back) axis of the
platform, which may be different than the platform
course (see platform_course). platform_roll_rate:
Platform is a structure or vehicle that serves as a
base for mounting sensors. Platforms include, but are
not limited to, satellites, aeroplanes, ships, buoys,
ground stations, and masts. Roll rate is the rate of
rotation about an axis (the X axis) that is
perpendicular to the local vertical axis (the Z axis)
and is coplanar with the nominal forward motion
direction of the platform. Roll rate might not include
changes in the ?at rest? rotation of the platform,
which may change over time. The direction for positive
values of roll rate is specified by an attribute named
direction. The value of the direction attribute is
"clockwise" if positive values of roll rate represent
the right side of the platform rising as viewed by an
observer on top of the platform facing forward. The
value of the direction attribute is "anticlockwise" if
positive values of roll rate represent the right side
of the platform falling. The directionality of roll
rate values is unspecified if no direction attribute is
present. platform_pitch_rate: Platform is a structure
or vehicle that serves as a base for mounting sensors.
Platforms include, but are not limited to, satellites,
aeroplanes, ships, buoys, ground stations, and masts.
Pitch rate is the rate of rotation about an axis (the Y
axis) that is perpendicular to both the local vertical
axis (the Z axis) and the nominal forward motion
direction of the platform. Pitch rate might not include
changes in the ?at rest? rotation of the platform,
which may change over time. The direction for positive
values of pitch rate is specified by an attribute named
direction. The value of the direction attribute is
"clockwise" if positive values of pitch rate represent
the front of the platform rising as viewed by an
observer on top of the platform facing forward. The
value of the direction attribute is "anticlockwise" if
positive values of pitch rate represent the front of
the platform falling. The directionality of pitch rate
values is unspecified if no direction attribute is
present. platform_yaw_rate: Platform is a structure or
vehicle that serves as a base for mounting sensors.
Platforms include, but are not limited to, satellites,
aeroplanes, ships, buoys, ground stations, and masts.
Yaw rate is the rate of rotation about the local
vertical axis (the Z axis). Yaw rate might not include
changes in the ?at rest? rotation of the platform,
which may change over time. The direction for positive
values of yaw rate is specified by an attribute named
direction. The value of the direction attribute is
"clockwise" if positive values of yaw rate represent
the front of the platform moving to the right as viewed
by an observer on top of the platform facing forward.
The value of the direction attribute is "anticlockwise"
if positive values of yaw rate represent the front of
the platform moving to the left. The directionality of
yaw rate values is unspecified if no direction
attribute is present. platform_surge_rate: Platform is
a structure or vehicle that serves as a base for
mounting sensors. Platforms include, but are not
limited to, satellites, aeroplanes, ships, buoys,
ground stations, and masts. Surge rate is the rate of
displacement along an axis (the X axis) that is
perpendicular to the local vertical axis (the Z axis)
and is coplanar with the nominal forward motion
direction of the platform. Surge rate might not include
changes in the ?at rest? position of the platform,
which may change over time. The direction for positive
values of surge rate is specified by an attribute named
direction. The value of the direction attribute is
"positive" if positive values of surge rate represent
the platform moving forward as viewed by an observer on
top of the platform facing forward. The value of the
direction attribute is "negative" if positive values of
surge rate represent the platform moving backward. The
directionality of surge rate values is unspecified if
no direction attribute is present. platform_sway_rate:
Platform is a structure or vehicle that serves as a
base for mounting sensors. Platforms include, but are
not limited to, satellites, aeroplanes, ships, buoys,
ground stations, and masts. Sway rate is the rate of
displacement along an axis (the Y axis) that is
perpendicular to both the local vertical axis (the Z
axis) and the nominal forward motion direction of the
platform. Sway rate might not include changes in the
?at rest? position of the platform, which may change
over time. The direction for positive values of sway
rate is specified by an attribute named direction. The
value of the direction attribute is "positive" if
positive values of sway rate represent the platform
moving left as viewed by an observer on top of the
platform facing forward. The value of the direction
attribute is "negative" if positive values of sway rate
represent the platform moving right. The directionality
of sway rate values is unspecified if no direction
attribute is present. platform_heave_rate: Platform is
a structure or vehicle that serves as a base for
mounting sensors. Platforms include, but are not
limited to, satellites, aeroplanes, ships, buoys,
ground stations, and masts. Heave rate is the rate of
displacement along the local vertical axis (the Z
axis). Heave rate might not include changes in the ?at
rest? position of the platform, which may change over
time. The direction for positive values of heave rate
is specified by an attribute named direction. The value
of the direction attribute is "positive" if positive
values of heave rate represent the platform moving up
as viewed by an observer on top of the platform facing
forward. The value of the direction attribute is
"negative" if positive values of heave rate represent
the platform moving down. The directionality of heave
rate values is unspecified if no direction attribute is
present. Grace and peace, Jim
--
CICS-NC <http://www.cicsnc.org/>Visit us on
Facebook <http://www.facebook.com/cicsnc> *Jim Biard*
*Research Scholar*
Cooperative Institute for Climate and Satellites NC <http://cicsnc.org/>
North Carolina State University <http://ncsu.edu/>
NOAA National Centers for Environmental Information <http://ncdc.noaa.gov/>
/formerly NOAA?s National Climatic Data Center/
151 Patton Ave, Asheville, NC 28801
e: jbi...@cicsnc.org <mailto:jbi...@cicsnc.org>
o: +1 828 271 4900
/Connect with us on Facebook for climate
<https://www.facebook.com/NOAANCEIclimate> and ocean and geophysics
<https://www.facebook.com/NOAANCEIoceangeo> information, and follow
us on Twitter at @NOAANCEIclimate
<https://twitter.com/NOAANCEIclimate> and @NOAANCEIocngeo
<https://twitter.com/NOAANCEIocngeo>. /
------------------------------------------------------------------------
This message (and any attachments) is for the recipient only. NERC
is subject to the Freedom of Information Act 2000 and the contents
of this email and any reply you make may be disclosed by NERC
unless it is exempt from release under the Act. Any material
supplied to NERC may be stored in an electronic records management
system.
------------------------------------------------------------------------
--
CICS-NC <http://www.cicsnc.org/> Visit us on
Facebook <http://www.facebook.com/cicsnc> *Jim Biard*
*Research Scholar*
Cooperative Institute for Climate and Satellites NC <http://cicsnc.org/>
North Carolina State University <http://ncsu.edu/>
NOAA National Centers for Environmental Information <http://ncdc.noaa.gov/>
/formerly NOAA?s National Climatic Data Center/
151 Patton Ave, Asheville, NC 28801
e: jbi...@cicsnc.org <mailto:jbi...@cicsnc.org>
o: +1 828 271 4900
/Connect with us on Facebook for climate
<https://www.facebook.com/NOAANCEIclimate> and ocean and geophysics
<https://www.facebook.com/NOAANCEIoceangeo> information, and follow
us on Twitter at @NOAANCEIclimate
<https://twitter.com/NOAANCEIclimate> and @NOAANCEIocngeo
<https://twitter.com/NOAANCEIocngeo>. /
_______________________________________________
CF-metadata mailing list
CF-metadata@cgd.ucar.edu
http://mailman.cgd.ucar.edu/mailman/listinfo/cf-metadata
