Jim's definitions work for me. I don't think we need to state the roll,
pitch and yaw need to be in angles. The Standard Name table conical
units indicate that. As for the order of the definitions I don't think
we have a standard that has been strictly enforced, and no matter what
order we put them in someone will prefer a different order.
Ken
On 2018-9-12 09:13, Nan Galbraith wrote:
> Hi again -
>> 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
> Or, maybe the definition of platform could come somewhere before the
> definition
> of starboard. Anywhere but at the start, unless there's a need for it
> to be there that
> I am missing.
>
> Also, do the definitions of roll, pitch and yaw need to explicitly
> state that these are
> angles, or is it enough that that's in the canonical units for these
> variables (and implied
> by '"rotation about an axis")?
>
> platform_roll_starboard_down: Roll is an angle of rotation about an
> axis that is perpendicular to
> the local vertical axis and is co-planar with the nominal forward
> motion direction of a 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. A 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. "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.
>
> Thanks - Nan
>>
>> Quoting Jim Biard <jbiard at 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-bounces at cgd.ucar.edu> on behalf of
>>>> Jim Biard <jbiard at cicsnc.org>
>>>> *Sent:* 11 September 2018 16:37
>>>> *To:* cf-metadata at 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 <jbgraybeal at mindspring.com>
>>>>>> <mailto:jbgraybeal at 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. <rkl at bodc.ac.uk
>>>>>> <mailto:rkl at bodc.ac.uk> <mailto:rkl at bodc.ac.uk>
>>>>>> <mailto:rkl at bodc.ac.uk>> wrote:
>>>>>>
>>>>>>> Dear Jim,
>>>>>>>
>>>>>>>
>>>>>>> Looking good to me.
>>>>>>>
>>>>>>>
>>>>>>> Cheers, Roy.
>>>>>>>
>>>>>>>
>>>>>>> ------------------------------------------------------------------------
>>>>>>> *From:* CF-metadata <cf-metadata-bounces at cgd.ucar.edu
>>>>>>> <mailto:cf-metadata-bounces at cgd.ucar.edu>
>>>>>>> <mailto:cf-metadata-bounces at cgd.ucar.edu>
>>>>>>> <mailto:cf-metadata-bounces at cgd.ucar.edu>> on behalf of Jim
>>>>>>> Biard <jbiard at cicsnc.org <mailto:jbiard at cicsnc.org>
>>>>>>> <mailto:jbiard at cicsnc.org> <mailto:jbiard at 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."
>>>>>>>>> <rkl at bodc.ac.uk> <mailto:rkl at bodc.ac.uk>
>>>>>>>>> <mailto:rkl at bodc.ac.uk> <mailto:rkl at 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-bounces at cgd.ucar.edu>
>>>>>>>>> <mailto:cf-metadata-bounces at cgd.ucar.edu>
>>>>>>>>> <mailto:cf-metadata-bounces at cgd.ucar.edu>
>>>>>>>>> <mailto:cf-metadata-bounces at cgd.ucar.edu> on behalf of
>>>>>>>>> Jonathan Gregory <j.m.gregory at reading.ac.uk>
>>>>>>>>> <mailto:j.m.gregory at reading.ac.uk>
>>>>>>>>> <mailto:j.m.gregory at reading.ac.uk>
>>>>>>>>> <mailto:j.m.gregory at 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
>>>>>>>>>> <jbiard at cicsnc.org> <mailto:jbiard at cicsnc.org>
>>>>>>>>>> <mailto:jbiard at cicsnc.org> <mailto:jbiard at 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-bounces at cgd.ucar.edu>
>>>>>>>>>>> <mailto:cf-metadata-bounces at cgd.ucar.edu>
>>>>>>>>>>> <mailto:cf-metadata-bounces at cgd.ucar.edu>
>>>>>>>>>>> <mailto:cf-metadata-bounces at cgd.ucar.edu> on behalf of Jim
>>>>>>>>>>> Biard <jbiard at cicsnc.org> <mailto:jbiard at cicsnc.org>
>>>>>>>>>>> <mailto:jbiard at cicsnc.org> <mailto:jbiard at 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<ngalbraith at whoi.edu>
>>>>>>>>>>>>>> <mailto:ngalbraith at whoi.edu> <mailto:ngalbraith at whoi.edu>
>>>>>>>>>>>>>> <mailto:ngalbraith at whoi.edu>-----
>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>> Date: Sun, 02 Sep 2018 11:57:33 -0400
>>>>>>>>>>>>>> From: Nan Galbraith<ngalbraith at whoi.edu>
>>>>>>>>>>>>>> <mailto:ngalbraith at whoi.edu> <mailto:ngalbraith at whoi.edu>
>>>>>>>>>>>>>> <mailto:ngalbraith at 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."<rkl at bodc.ac.uk> <mailto:rkl at bodc.ac.uk>
>>>>>>>>>>>>>>> <mailto:rkl at bodc.ac.uk> <mailto:rkl at bodc.ac.uk>
>>>>>>>>>>>>>>> <mailto:rkl at bodc.ac.uk> <mailto:rkl at bodc.ac.uk>
>>>>>>>>>>>>>>> <mailto:rkl at bodc.ac.uk> <mailto:rkl at 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<jbiard at cicsnc.org>
>>>>>>>>>>>>>>>> <mailto:jbiard at cicsnc.org> <mailto:jbiard at cicsnc.org>
>>>>>>>>>>>>>>>> <mailto:jbiard at 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
>>>>>>>>>>>>>>>> <kkehoe at ou.edu> <mailto:kkehoe at ou.edu>
>>>>>>>>>>>>>>>> <mailto:kkehoe at ou.edu> <mailto:kkehoe at ou.edu>
>>>>>>>>>>>>>>>> <mailto:kkehoe at ou.edu> <mailto:kkehoe at ou.edu>
>>>>>>>>>>>>>>>> <mailto:kkehoe at ou.edu> <mailto:kkehoe at ou.edu>
>>>>>>>>>>>>>>>> Date: Thu, 30 Aug 2018 12:05:44 -0600
>>>>>>>>>>>>>>>> From: Kenneth Kehoe<kkehoe at ou.edu>
>>>>>>>>>>>>>>>> <mailto:kkehoe at ou.edu> <mailto:kkehoe at ou.edu>
>>>>>>>>>>>>>>>> <mailto:kkehoe at 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
>>>>>>>>>>>>>>>> <jbiard at cicsnc.org <mailto:jbiard at cicsnc.org>
>>>>>>>>>>>>>>>> <mailto:jbiard at cicsnc.org>
>>>>>>>>>>>>>>>> <mailto:jbiard at 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<jbiard at cicsnc.org>
>>>>>>>>>>>>>>>> <mailto:jbiard at cicsnc.org> <mailto:jbiard at cicsnc.org>
>>>>>>>>>>>>>>>> <mailto:jbiard at 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
>>>>>>>>>>>>>>>>
>>>>>
>>>>
>
>
--
Kenneth E. Kehoe
Research Associate - University of Oklahoma
Cooperative Institute for Mesoscale Meteorological Studies
ARM Climate Research Facility - Data Quality Office
e-mail: kkehoe at ou.edu | Office: 303-497-4754 | Cell: 405-826-0299
Received on Wed Sep 12 2018 - 11:23:25 BST
