⇐ ⇒

[CF-metadata] Platform Heave

From: Jim Biard <jbiard>
Date: Tue, 4 Sep 2018 09:37:00 -0400

Hi.

If that's the general consensus, then we can go that general direction.
I'll prepare pairs of everything.

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 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.

Grace and peace,

Jim


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> -----
>
>> Date: Sun, 02 Sep 2018 11:57:33 -0400
>> From: Nan Galbraith <ngalbraith at whoi.edu>
>> To: "Lowry, Roy K." <rkl at bodc.ac.uk>
>> Cc: cf-metadata at cgd.ucar.edu
>> Subject: Re: [CF-metadata] Platform Heave
>> User-Agent: Internet Messaging Program (IMP) H4 (5.0.23)
>>
>> 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>:
>>
>>> 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.
>>>
>>>
>>> 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: 31 August 2018 14:38
>>> To: cf-metadata at cgd.ucar.edu
>>> Subject: Re: [CF-metadata] Platform Heave
>>>
>>>
>>> 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> -----
>>>
>>>
>>>
>>> Date: Thu, 30 Aug 2018 12:05:44 -0600
>>> From: Kenneth Kehoe <kkehoe at ou.edu><mailto:kkehoe at ou.edu>
>>> To: cf-metadata at cgd.ucar.edu<mailto:cf-metadata at cgd.ucar.edu>
>>> Subject: Re: [CF-metadata] Platform Heave
>>> User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.13; rv:60.0)
>>> Gecko/20100101 Thunderbird/60.0
>>>
>>> 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
>>> retrograde.
>>>
>>> https://www.hindawi.com/journals/mpe/2010/934714/
>>> <https://urldefense.proofpoint.com/v2/url?u=https-3A__www.hindawi.com_journals_mpe_2010_934714_&d=DwMFaQ&c=qKdtBuuu6dQK9MsRUVJ2DPXW6oayO8fu4TfEHS8sGNk&r=Vm7o2ZGxPkkqRuPs8nVMVQ&m=V30oufQn7eoscpwV3fkPj-Rzw4SsBmtwWpTQ8PZaDgQ&s=NV5FW-iZ7Ml9G3tz6Dg4tXjiM7w1mDsctSx_tWbiTmc&e=><https://urldefense.proofpoint.com/v2/url?u=https-3A__www.hindawi.com_journals_mpe_2010_934714_&d=DwMFaQ&c=qKdtBuuu6dQK9MsRUVJ2DPXW6oayO8fu4TfEHS8sGNk&r=Vm7o2ZGxPkkqRuPs8nVMVQ&m=V30oufQn7eoscpwV3fkPj-Rzw4SsBmtwWpTQ8PZaDgQ&s=NV5FW-iZ7Ml9G3tz6Dg4tXjiM7w1mDsctSx_tWbiTmc&e=>
>>>
>>> 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
>>>
>>>
>>>
>>>
>>> _______________________________________________
>>> CF-metadata mailing list
>>> CF-metadata at cgd.ucar.edu<mailto:CF-metadata at cgd.ucar.edu>
>>> <mailto:CF-metadata at cgd.ucar.edu><mailto:CF-metadata at cgd.ucar.edu>
>>> http://mailman.cgd.ucar.edu/mailman/listinfo/cf-metadata <https://urldefense.proofpoint.com/v2/url?u=http-3A__mailman.cgd.ucar.edu_mailman_listinfo_cf-2Dmetadata&d=DwMFaQ&c=qKdtBuuu6dQK9MsRUVJ2DPXW6oayO8fu4TfEHS8sGNk&r=Vm7o2ZGxPkkqRuPs8nVMVQ&m=V30oufQn7eoscpwV3fkPj-Rzw4SsBmtwWpTQ8PZaDgQ&s=aEFMW9rC-ZIMfpnOfGtNzFe4-ieMDTvZ6FT1YaDGMzk&e=><https://urldefense.proofpoint.com/v2/url?u=http-3A__mailman.cgd.ucar.edu_mailman_listinfo_cf-2Dmetadata&d=DwMFaQ&c=qKdtBuuu6dQK9MsRUVJ2DPXW6oayO8fu4TfEHS8sGNk&r=Vm7o2ZGxPkkqRuPs8nVMVQ&m=V30oufQn7eoscpwV3fkPj-Rzw4SsBmtwWpTQ8PZaDgQ&s=aEFMW9rC-ZIMfpnOfGtNzFe4-ieMDTvZ6FT1YaDGMzk&e=>
>>>
>>>
>>> -- John Helly, University of California, San Diego / San
>>> Diego Supercomputer Center / Scripps Institution of Oceanography
>>> / 760 840 8660 mobile /http://www.sdsc.edu/~hellyj <https://urldefense.proofpoint.com/v2/url?u=http-3A__www.sdsc.edu_-257Ehellyj&d=DwMFaQ&c=qKdtBuuu6dQK9MsRUVJ2DPXW6oayO8fu4TfEHS8sGNk&r=Vm7o2ZGxPkkqRuPs8nVMVQ&m=V30oufQn7eoscpwV3fkPj-Rzw4SsBmtwWpTQ8PZaDgQ&s=t3yS7bwFeIbplaq59rJwZjTCr0nh-AAbloaOEdxwExk&e=><https://urldefense.proofpoint.com/v2/url?u=http-3A__www.sdsc.edu_-257Ehellyj&d=DwMFaQ&c=qKdtBuuu6dQK9MsRUVJ2DPXW6oayO8fu4TfEHS8sGNk&r=Vm7o2ZGxPkkqRuPs8nVMVQ&m=V30oufQn7eoscpwV3fkPj-Rzw4SsBmtwWpTQ8PZaDgQ&s=t3yS7bwFeIbplaq59rJwZjTCr0nh-AAbloaOEdxwExk&e=>
>>> ORCID ID:orcid.org/0000-0002-3779-0603 <https://urldefense.proofpoint.com/v2/url?u=http-3A__orcid.org_0000-2D0002-2D3779-2D0603&d=DwMFaQ&c=qKdtBuuu6dQK9MsRUVJ2DPXW6oayO8fu4TfEHS8sGNk&r=Vm7o2ZGxPkkqRuPs8nVMVQ&m=V30oufQn7eoscpwV3fkPj-Rzw4SsBmtwWpTQ8PZaDgQ&s=6qTo44N_z3oeg5Su7f35nDe-nUQIgvAxqIFhSoDDwp4&e=><https://urldefense.proofpoint.com/v2/url?u=http-3A__orcid.org_0000-2D0002-2D3779-2D0603&d=DwMFaQ&c=qKdtBuuu6dQK9MsRUVJ2DPXW6oayO8fu4TfEHS8sGNk&r=Vm7o2ZGxPkkqRuPs8nVMVQ&m=V30oufQn7eoscpwV3fkPj-Rzw4SsBmtwWpTQ8PZaDgQ&s=6qTo44N_z3oeg5Su7f35nDe-nUQIgvAxqIFhSoDDwp4&e=>
>>>
>>>
>>> -- CICS-NC
>>> <https://urldefense.proofpoint.com/v2/url?u=http-3A__www.cicsnc.org_&d=DwMFaQ&c=qKdtBuuu6dQK9MsRUVJ2DPXW6oayO8fu4TfEHS8sGNk&r=Vm7o2ZGxPkkqRuPs8nVMVQ&m=V30oufQn7eoscpwV3fkPj-Rzw4SsBmtwWpTQ8PZaDgQ&s=x6gV6lXbbLkdSUM51Wmjdo76fXshvuWXWY9xQaf4LY4&e=><https://urldefense.proofpoint.com/v2/url?u=http-3A__www.cicsnc.org_&d=DwMFaQ&c=qKdtBuuu6dQK9MsRUVJ2DPXW6oayO8fu4TfEHS8sGNk&r=Vm7o2ZGxPkkqRuPs8nVMVQ&m=V30oufQn7eoscpwV3fkPj-Rzw4SsBmtwWpTQ8PZaDgQ&s=x6gV6lXbbLkdSUM51Wmjdo76fXshvuWXWY9xQaf4LY4&e=>
>>> Visit us on
>>> Facebook
>>> <https://urldefense.proofpoint.com/v2/url?u=http-3A__www.facebook.com_cicsnc&d=DwMFaQ&c=qKdtBuuu6dQK9MsRUVJ2DPXW6oayO8fu4TfEHS8sGNk&r=Vm7o2ZGxPkkqRuPs8nVMVQ&m=V30oufQn7eoscpwV3fkPj-Rzw4SsBmtwWpTQ8PZaDgQ&s=QlBTCEJ-1zY8HYYE-fNxyp7W2lFizXxrb6KMRXUvDMg&e=><https://urldefense.proofpoint.com/v2/url?u=http-3A__www.facebook.com_cicsnc&d=DwMFaQ&c=qKdtBuuu6dQK9MsRUVJ2DPXW6oayO8fu4TfEHS8sGNk&r=Vm7o2ZGxPkkqRuPs8nVMVQ&m=V30oufQn7eoscpwV3fkPj-Rzw4SsBmtwWpTQ8PZaDgQ&s=QlBTCEJ-1zY8HYYE-fNxyp7W2lFizXxrb6KMRXUvDMg&e=>
>>> *Jim Biard*
>>> *Research Scholar*
>>> Cooperative Institute for Climate and Satellites NC
>>> <https://urldefense.proofpoint.com/v2/url?u=http-3A__cicsnc.org_&d=DwMFaQ&c=qKdtBuuu6dQK9MsRUVJ2DPXW6oayO8fu4TfEHS8sGNk&r=Vm7o2ZGxPkkqRuPs8nVMVQ&m=V30oufQn7eoscpwV3fkPj-Rzw4SsBmtwWpTQ8PZaDgQ&s=FsLkqUXutAcXAPp22ZFFI6PUFlxtYMRYP65HFKMn6wQ&e=><https://urldefense.proofpoint.com/v2/url?u=http-3A__cicsnc.org_&d=DwMFaQ&c=qKdtBuuu6dQK9MsRUVJ2DPXW6oayO8fu4TfEHS8sGNk&r=Vm7o2ZGxPkkqRuPs8nVMVQ&m=V30oufQn7eoscpwV3fkPj-Rzw4SsBmtwWpTQ8PZaDgQ&s=FsLkqUXutAcXAPp22ZFFI6PUFlxtYMRYP65HFKMn6wQ&e=>
>>>
>>> North Carolina State University
>>> <https://urldefense.proofpoint.com/v2/url?u=http-3A__ncsu.edu_&d=DwMFaQ&c=qKdtBuuu6dQK9MsRUVJ2DPXW6oayO8fu4TfEHS8sGNk&r=Vm7o2ZGxPkkqRuPs8nVMVQ&m=V30oufQn7eoscpwV3fkPj-Rzw4SsBmtwWpTQ8PZaDgQ&s=hkh8KblCtKqdp0zgN1OJbRBL0hfQw6tQwazcgNBCYCM&e=><https://urldefense.proofpoint.com/v2/url?u=http-3A__ncsu.edu_&d=DwMFaQ&c=qKdtBuuu6dQK9MsRUVJ2DPXW6oayO8fu4TfEHS8sGNk&r=Vm7o2ZGxPkkqRuPs8nVMVQ&m=V30oufQn7eoscpwV3fkPj-Rzw4SsBmtwWpTQ8PZaDgQ&s=hkh8KblCtKqdp0zgN1OJbRBL0hfQw6tQwazcgNBCYCM&e=>
>>>
>>> NOAA National Centers for Environmental Information
>>> <https://urldefense.proofpoint.com/v2/url?u=http-3A__ncdc.noaa.gov_&d=DwMFaQ&c=qKdtBuuu6dQK9MsRUVJ2DPXW6oayO8fu4TfEHS8sGNk&r=Vm7o2ZGxPkkqRuPs8nVMVQ&m=V30oufQn7eoscpwV3fkPj-Rzw4SsBmtwWpTQ8PZaDgQ&s=lRLoOpPkER90BdM_TLc6QrJjgxz8V1gUTPLG5FHbLNk&e=><https://urldefense.proofpoint.com/v2/url?u=http-3A__ncdc.noaa.gov_&d=DwMFaQ&c=qKdtBuuu6dQK9MsRUVJ2DPXW6oayO8fu4TfEHS8sGNk&r=Vm7o2ZGxPkkqRuPs8nVMVQ&m=V30oufQn7eoscpwV3fkPj-Rzw4SsBmtwWpTQ8PZaDgQ&s=lRLoOpPkER90BdM_TLc6QrJjgxz8V1gUTPLG5FHbLNk&e=>
>>>
>>> /formerly NOAA?s National Climatic Data Center/
>>> 151 Patton Ave, Asheville, NC 28801
>>> e: jbiard at cicsnc.org<mailto:jbiard at cicsnc.org>
>>> <mailto:jbiard at cicsnc.org><mailto:jbiard at cicsnc.org>
>>> o: +1 828 271 4900
>>>
>>> /Connect with us on Facebook for climate
>>> <https://urldefense.proofpoint.com/v2/url?u=https-3A__www.facebook.com_NOAANCEIclimate&d=DwMFaQ&c=qKdtBuuu6dQK9MsRUVJ2DPXW6oayO8fu4TfEHS8sGNk&r=Vm7o2ZGxPkkqRuPs8nVMVQ&m=V30oufQn7eoscpwV3fkPj-Rzw4SsBmtwWpTQ8PZaDgQ&s=IHiNI2oKTMXCgS6xh6TruNzh-tpMlrDgwrCErMx3Z-0&e=><https://urldefense.proofpoint.com/v2/url?u=https-3A__www.facebook.com_NOAANCEIclimate&d=DwMFaQ&c=qKdtBuuu6dQK9MsRUVJ2DPXW6oayO8fu4TfEHS8sGNk&r=Vm7o2ZGxPkkqRuPs8nVMVQ&m=V30oufQn7eoscpwV3fkPj-Rzw4SsBmtwWpTQ8PZaDgQ&s=IHiNI2oKTMXCgS6xh6TruNzh-tpMlrDgwrCErMx3Z-0&e=>
>>> and ocean and geophysics
>>> <https://urldefense.proofpoint.com/v2/url?u=https-3A__www.facebook.com_NOAANCEIoceangeo&d=DwMFaQ&c=qKdtBuuu6dQK9MsRUVJ2DPXW6oayO8fu4TfEHS8sGNk&r=Vm7o2ZGxPkkqRuPs8nVMVQ&m=V30oufQn7eoscpwV3fkPj-Rzw4SsBmtwWpTQ8PZaDgQ&s=9i9XGUDVz9JclOsGWxIvmi1O2ulu_Ta_r0Ia8NwEbKM&e=><https://urldefense.proofpoint.com/v2/url?u=https-3A__www.facebook.com_NOAANCEIoceangeo&d=DwMFaQ&c=qKdtBuuu6dQK9MsRUVJ2DPXW6oayO8fu4TfEHS8sGNk&r=Vm7o2ZGxPkkqRuPs8nVMVQ&m=V30oufQn7eoscpwV3fkPj-Rzw4SsBmtwWpTQ8PZaDgQ&s=9i9XGUDVz9JclOsGWxIvmi1O2ulu_Ta_r0Ia8NwEbKM&e=>
>>> information, and follow us on Twitter at _at_NOAANCEIclimate
>>> <https://urldefense.proofpoint.com/v2/url?u=https-3A__twitter.com_NOAANCEIclimate&d=DwMFaQ&c=qKdtBuuu6dQK9MsRUVJ2DPXW6oayO8fu4TfEHS8sGNk&r=Vm7o2ZGxPkkqRuPs8nVMVQ&m=V30oufQn7eoscpwV3fkPj-Rzw4SsBmtwWpTQ8PZaDgQ&s=XMw4fQ1_EhOoPwwVIa2gAsjDFQNzOIJ4sXv6DlAVq_4&e=><https://urldefense.proofpoint.com/v2/url?u=https-3A__twitter.com_NOAANCEIclimate&d=DwMFaQ&c=qKdtBuuu6dQK9MsRUVJ2DPXW6oayO8fu4TfEHS8sGNk&r=Vm7o2ZGxPkkqRuPs8nVMVQ&m=V30oufQn7eoscpwV3fkPj-Rzw4SsBmtwWpTQ8PZaDgQ&s=XMw4fQ1_EhOoPwwVIa2gAsjDFQNzOIJ4sXv6DlAVq_4&e=>
>>> and _at_NOAANCEIocngeo
>>> <https://urldefense.proofpoint.com/v2/url?u=https-3A__twitter.com_NOAANCEIocngeo&d=DwMFaQ&c=qKdtBuuu6dQK9MsRUVJ2DPXW6oayO8fu4TfEHS8sGNk&r=Vm7o2ZGxPkkqRuPs8nVMVQ&m=V30oufQn7eoscpwV3fkPj-Rzw4SsBmtwWpTQ8PZaDgQ&s=rQdLOnos9rBDcbJXGsD7CgZgcW2493WTB3e8bO8bqVo&e=><https://urldefense.proofpoint.com/v2/url?u=https-3A__twitter.com_NOAANCEIocngeo&d=DwMFaQ&c=qKdtBuuu6dQK9MsRUVJ2DPXW6oayO8fu4TfEHS8sGNk&r=Vm7o2ZGxPkkqRuPs8nVMVQ&m=V30oufQn7eoscpwV3fkPj-Rzw4SsBmtwWpTQ8PZaDgQ&s=rQdLOnos9rBDcbJXGsD7CgZgcW2493WTB3e8bO8bqVo&e=>.
>>> /
>>>
>>>
>>> _______________________________________________
>>> CF-metadata mailing list
>>> CF-metadata at cgd.ucar.edu<mailto:CF-metadata at cgd.ucar.edu>
>>> <mailto:CF-metadata at cgd.ucar.edu><mailto:CF-metadata at cgd.ucar.edu>
>>> http://mailman.cgd.ucar.edu/mailman/listinfo/cf-metadata
>>> <https://urldefense.proofpoint.com/v2/url?u=http-3A__mailman.cgd.ucar.edu_mailman_listinfo_cf-2Dmetadata&d=DwMFaQ&c=qKdtBuuu6dQK9MsRUVJ2DPXW6oayO8fu4TfEHS8sGNk&r=Vm7o2ZGxPkkqRuPs8nVMVQ&m=V30oufQn7eoscpwV3fkPj-Rzw4SsBmtwWpTQ8PZaDgQ&s=aEFMW9rC-ZIMfpnOfGtNzFe4-ieMDTvZ6FT1YaDGMzk&e=><https://urldefense.proofpoint.com/v2/url?u=http-3A__mailman.cgd.ucar.edu_mailman_listinfo_cf-2Dmetadata&d=DwMFaQ&c=qKdtBuuu6dQK9MsRUVJ2DPXW6oayO8fu4TfEHS8sGNk&r=Vm7o2ZGxPkkqRuPs8nVMVQ&m=V30oufQn7eoscpwV3fkPj-Rzw4SsBmtwWpTQ8PZaDgQ&s=aEFMW9rC-ZIMfpnOfGtNzFe4-ieMDTvZ6FT1YaDGMzk&e=>
>>>
>>>
>>> _______________________________________________
>>> CF-metadata mailing list
>>> CF-metadata at cgd.ucar.edu<mailto:CF-metadata at cgd.ucar.edu>
>>> http://mailman.cgd.ucar.edu/mailman/listinfo/cf-metadata
>>>
>>>
>>> --
>>> 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<mailto:kkehoe at ou.edu> | Office:
>>> 303-497-4754 | Cell: 405-826-0299
>>>
>>>
>>>
>>> _______________________________________________
>>> CF-metadata mailing list
>>> CF-metadata at cgd.ucar.edu<mailto:CF-metadata at cgd.ucar.edu>
>>> http://mailman.cgd.ucar.edu/mailman/listinfo/cf-metadata
>>>
>>>
>>> ----- End forwarded message -----
>>> _______________________________________________
>>> CF-metadata mailing list
>>> CF-metadata at cgd.ucar.edu<mailto:CF-metadata at cgd.ucar.edu>
>>> http://mailman.cgd.ucar.edu/mailman/listinfo/cf-metadata
>>>
>>>
>>> --
>>> [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
>>>
>>> Connect with us on Facebook for
>>> climate<https://www.facebook.com/NOAANCEIclimate> and ocean and
>>> geophysics<https://www.facebook.com/NOAANCEIoceangeo> information,
>>> and follow us on Twitter at
>>> _at_NOAANCEIclimate<https://twitter.com/NOAANCEIclimate> and
>>> _at_NOAANCEIocngeo<https://twitter.com/NOAANCEIocngeo>.
>>>
>>> ________________________________
>>> This message (and any attachments) is for the recipient only. NERC
>>> is subject to the Freedom of Information Act 2000 and the contents
>>> of this email and any reply you make may be disclosed by NERC
>>> unless it is exempt from release under the Act. Any material
>>> supplied to NERC may be stored in an electronic records management
>>> system.
>>> ________________________________
>>
>>
>> _______________________________________________
>> CF-metadata mailing list
>> CF-metadata at cgd.ucar.edu
>> http://mailman.cgd.ucar.edu/mailman/listinfo/cf-metadata
> ----- End forwarded message -----
> _______________________________________________
> CF-metadata mailing list
> CF-metadata at cgd.ucar.edu
> http://mailman.cgd.ucar.edu/mailman/listinfo/cf-metadata

-- 
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
/Connect with us on Facebook for climate 
<https://www.facebook.com/NOAANCEIclimate> and ocean and geophysics 
<https://www.facebook.com/NOAANCEIoceangeo> information, and follow us 
on Twitter at _at_NOAANCEIclimate <https://twitter.com/NOAANCEIclimate> and 
_at_NOAANCEIocngeo <https://twitter.com/NOAANCEIocngeo>. /
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