[CF-metadata] Platform Heave

Jim Biard jbiard at cicsnc.org
Wed Sep 12 07:16:08 MDT 2018


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
>>>>>>>>>>>>>
>>
>
> -- 
> CICS-NC <http://www.cicsnc.org/>Visit us on
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> ------------------------------------------------------------------------

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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: jbiard at cicsnc.org <mailto:jbiard at cicsnc.org>
o: +1 828 271 4900

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