Hi.
If everyone is happy with this, I guess we need to get Alison's
attention. :-) Last call!
Grace and peace,
Jim
On 9/13/18 4:09 AM, Lowry, Roy K. wrote:
>
> Dear Jim, Ken and Nan,
>
>
> An impressive piece of work when seen in its entirety. Well done Jim!
>
>
> I totally agree with Jim and Ken about there being no need for 'angle'.
>
>
> I have mixed feelings about the ordering of the definition clauses,
> but can see the logic in Jim's reasoning and so can accept his ordering.
>
>
> 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
> Kenneth Kehoe <kkehoe at ou.edu>
> *Sent:* 12 September 2018 18:23
> *To:* cf-metadata at cgd.ucar.edu
> *Subject:* Re: [CF-metadata] Platform Heave
> Jim's definitions work for me. I don't think we need to state the roll,
> pitch and yaw need to be in angles. The Standard Name table conical
> units indicate that. As for the order of the definitions I don't think
> we have a standard that has been strictly enforced, and no matter what
> order we put them in someone will prefer a different order.
>
> Ken
>
>
> On 2018-9-12 09:13, Nan Galbraith wrote:
> > Hi again -
> >> Nice, thanks, Jim.
> >>
> >> My only suggestion, after a very quick read-through, is that we could
> >> put the definition of platform at the end of the variable's definition.
> >> That makes it much easier to scan these for the right term.
> >>
> >> Cheers - Nan
> > Or, maybe the definition of platform could come somewhere before the
> > definition
> > of starboard. Anywhere but at the start, unless there's a need for it
> > to be there that
> > I am missing.
> >
> > Also, do the definitions of roll, pitch and yaw need to explicitly
> > state that these are
> > angles, or is it enough that that's in the canonical units for these
> > variables (and implied
> > by '"rotation about an axis")?
> >
> > platform_roll_starboard_down: Roll is an angle of rotation about an
> > axis that is perpendicular to
> > the local vertical axis and is co-planar with the nominal forward
> > motion direction of a platform.
> > Roll is relative to the "at rest" rotation of the platform with
> > respect to the axis of rotation. The "at rest"
> > rotation of the platform may change over time. A platform is a
> > structure or vehicle that serves as a
> > base for mounting sensors. Platforms include, but are not limited to,
> > satellites, aeroplanes, ships,
> > buoys, ground stations, and masts. "Starboard down" indicates that
> > positive values of roll represent
> > the right side of the platform falling as viewed by an observer on top
> > of the platform facing forward.
> >
> > Thanks - Nan
> >>
> >> Quoting Jim Biard <jbiard at cicsnc.org>:
> >>
> >>> Hi.
> >>>
> >>>
> >>> How about these definitions?
> >>>
> >>>
> >>> Jim
> >>>
> >>>
> >>> ==================
> >>>
> >>>
> >>> platform_roll_starboard_down: Platform is a structure or vehicle
> >>> that serves as a base for mounting sensors. Platforms include, but
> >>> are not limited to, satellites, aeroplanes, ships, buoys, ground
> >>> stations, and masts. Roll is a rotation about an axis that is
> >>> perpendicular to the local vertical axis and is coplanar with the
> >>> nominal forward motion direction of the platform. Roll is relative
> >>> to the ?at rest? rotation of the platform with respect to the axis
> >>> of rotation. The ?at rest? rotation of the platform may change over
> >>> time. "Starboard down" indicates that positive values of roll
> >>> represent the right side of the platform falling as viewed by an
> >>> observer on top of the platform facing forward.
> >>>
> >>> platform_roll_starboard_up: Platform is a structure or vehicle that
> >>> serves as a base for mounting sensors. Platforms include, but are
> >>> not limited to, satellites, aeroplanes, ships, buoys, ground
> >>> stations, and masts. Roll is a rotation about an axis that is
> >>> perpendicular to the local vertical axis and is coplanar with the
> >>> nominal forward motion direction of the platform. Roll is relative
> >>> to the ?at rest? rotation of the platform with respect to the axis
> >>> of rotation. The ?at rest? rotation of the platform may change over
> >>> time. "Starboard up" indicates that positive values of roll
> >>> represent the right side of the platform rising as viewed by an
> >>> observer on top of the platform facing forward.
> >>>
> >>> platform_roll_rate_starboard_down: Platform is a structure or
> >>> vehicle that serves as a base for mounting sensors. Platforms
> >>> include, but are not limited to, satellites, aeroplanes, ships,
> >>> buoys, ground stations, and masts. "Roll rate" is the rate of
> >>> rotation about an axis that is perpendicular to the local vertical
> >>> axis and is coplanar with the nominal forward motion direction of
> >>> the platform. Roll rate might not include changes to the ?at rest?
> >>> rotation of the platform with respect to the axis of rotation, which
> >>> may change over time. "Starboard down" indicates that positive
> >>> values of roll rate represent the right side of the platform falling
> >>> as viewed by an observer on top of the platform facing forward.
> >>>
> >>> platform_roll_rate_starboard_up: Platform is a structure or vehicle
> >>> that serves as a base for mounting sensors. Platforms include, but
> >>> are not limited to, satellites, aeroplanes, ships, buoys, ground
> >>> stations, and masts. "Roll rate" is the rate of rotation about an
> >>> axis that is perpendicular to the local vertical axis and is
> >>> coplanar with the nominal forward motion direction of the platform.
> >>> Roll rate might not include changes to the ?at rest? rotation of the
> >>> platform with respect to the axis of rotation, which may change over
> >>> time. "Starboard up" indicates that positive values of roll rate
> >>> represent the right side of the platform rising as viewed by an
> >>> observer on top of the platform facing forward.
> >>>
> >>> platform_pitch_fore_up: Platform is a structure or vehicle that
> >>> serves as a base for mounting sensors. Platforms include, but are
> >>> not limited to, satellites, aeroplanes, ships, buoys, ground
> >>> stations, and masts. Pitch is a rotation about an axis that is
> >>> perpendicular to both the local vertical axis and the nominal
> >>> forward motion direction of the platform. Pitch is relative to the
> >>> ?at rest? rotation of the platform with respect to the axis of
> >>> rotation. The ?at rest? rotation of the platform may change over
> >>> time. "Fore up" indicates that positive values of pitch represent
> >>> the front of the platform rising as viewed by an observer on top of
> >>> the platform facing forward.
> >>>
> >>> platform_pitch_fore_down: Platform is a structure or vehicle that
> >>> serves as a base for mounting sensors. Platforms include, but are
> >>> not limited to, satellites, aeroplanes, ships, buoys, ground
> >>> stations, and masts. Pitch is a rotation about an axis that is
> >>> perpendicular to both the local vertical axis and the nominal
> >>> forward motion direction of the platform. Pitch is relative to the
> >>> ?at rest? rotation of the platform with respect to the axis of
> >>> rotation. The ?at rest? rotation of the platform may change over
> >>> time. "Fore down" indicates that positive values of pitch represent
> >>> the front of the platform falling as viewed by an observer on top of
> >>> the platform facing forward.
> >>>
> >>> platform_pitch_rate_fore_up: Platform is a structure or vehicle that
> >>> serves as a base for mounting sensors. Platforms include, but are
> >>> not limited to, satellites, aeroplanes, ships, buoys, ground
> >>> stations, and masts. "Pitch rate" is the rate of rotation about an
> >>> axis that is perpendicular to both the local vertical axis and the
> >>> nominal forward motion direction of the platform. Pitch rate might
> >>> not include changes to the ?at rest? rotation of the platform with
> >>> respect to the axis of rotation, which may change over time. "Fore
> >>> up" indicates that positive values of pitch rate represent the front
> >>> of the platform rising as viewed by an observer on top of the
> >>> platform facing forward.
> >>>
> >>> platform_pitch_rate_fore_down: Platform is a structure or vehicle
> >>> that serves as a base for mounting sensors. Platforms include, but
> >>> are not limited to, satellites, aeroplanes, ships, buoys, ground
> >>> stations, and masts. "Pitch rate" is the rate of rotation about an
> >>> axis that is perpendicular to both the local vertical axis and the
> >>> nominal forward motion direction of the platform. Pitch rate might
> >>> not include changes to the ?at rest? rotation of the platform with
> >>> respect to the axis of rotation, which may change over time. "Fore
> >>> down" indicates that positive values of pitch rate represent the
> >>> front of the platform falling as viewed by an observer on top of the
> >>> platform facing forward.
> >>>
> >>> platform_yaw_fore_starboard: Platform is a structure or vehicle that
> >>> serves as a base for mounting sensors. Platforms include, but are
> >>> not limited to, satellites, aeroplanes, ships, buoys, ground
> >>> stations, and masts. Yaw is a rotation about the axis of rotation.
> >>> Yaw is relative to the ?at rest? rotation of the platform with
> >>> respect to the axis of rotation. The ?at rest? rotation of the
> >>> platform may change over time. "Fore starboard" indicates that
> >>> positive values of yaw represent the front of the platform moving to
> >>> the right as viewed by an observer on top of the platform facing
> >>> forward.
> >>>
> >>> platform_yaw_fore_port: Platform is a structure or vehicle that
> >>> serves as a base for mounting sensors. Platforms include, but are
> >>> not limited to, satellites, aeroplanes, ships, buoys, ground
> >>> stations, and masts. Yaw is a rotation about the axis of rotation.
> >>> Yaw is relative to the ?at rest? rotation of the platform with
> >>> respect to the axis of rotation. The ?at rest? rotation of the
> >>> platform may change over time. "Fore port" indicates that positive
> >>> values of yaw represent the front of the platform moving to the left
> >>> as viewed by an observer on top of the platform facing forward.
> >>>
> >>> platform_yaw_rate_fore_starboard: Platform is a structure or vehicle
> >>> that serves as a base for mounting sensors. Platforms include, but
> >>> are not limited to, satellites, aeroplanes, ships, buoys, ground
> >>> stations, and masts. "Yaw rate" is the rate of rotation about the
> >>> axis of rotation. Yaw rate might not include changes to the ?at
> >>> rest? rotation of the platform with respect to the axis of rotation,
> >>> which may change over time. "Fore starboard" indicates that positive
> >>> values of yaw rate represent the front of the platform moving to the
> >>> right as viewed by an observer on top of the platform facing forward.
> >>>
> >>> platform_yaw_rate_fore_port: Platform is a structure or vehicle that
> >>> serves as a base for mounting sensors. Platforms include, but are
> >>> not limited to, satellites, aeroplanes, ships, buoys, ground
> >>> stations, and masts. "Yaw rate" is the rate of rotation about the
> >>> axis of rotation. Yaw rate might not include changes to the ?at
> >>> rest? rotation of the platform with respect to the axis of rotation,
> >>> which may change over time. "Fore port" indicates that positive
> >>> values of yaw rate represent the front of the platform moving to the
> >>> left as viewed by an observer on top of the platform facing forward.
> >>>
> >>> platform_surge_fore: Platform is a structure or vehicle that serves
> >>> as a base for mounting sensors. Platforms include, but are not
> >>> limited to, satellites, aeroplanes, ships, buoys, ground stations,
> >>> and masts. Surge is a displacement along an axis that is
> >>> perpendicular to the local vertical axis and is coplanar with the
> >>> nominal forward motion direction of the platform. Surge is relative
> >>> to the ?at rest? position of the platform with respect to the axis
> >>> of displacement. The ?at rest? position of the platform may change
> >>> over time. "Fore" indicates that positive values of surge represent
> >>> the platform moving forward as viewed by an observer on top of the
> >>> platform facing forward.
> >>>
> >>> platform_surge_aft: Platform is a structure or vehicle that serves
> >>> as a base for mounting sensors. Platforms include, but are not
> >>> limited to, satellites, aeroplanes, ships, buoys, ground stations,
> >>> and masts. Surge is a displacement along an axis that is
> >>> perpendicular to the local vertical axis and is coplanar with the
> >>> nominal forward motion direction of the platform. Surge is relative
> >>> to the ?at rest? position of the platform with respect to the axis
> >>> of displacement. The ?at rest? position of the platform may change
> >>> over time. "Aft" indicates that positive values of surge represent
> >>> the platform moving backward as viewed by an observer on top of the
> >>> platform facing forward.
> >>>
> >>> platform_surge_rate_fore: Platform is a structure or vehicle that
> >>> serves as a base for mounting sensors. Platforms include, but are
> >>> not limited to, satellites, aeroplanes, ships, buoys, ground
> >>> stations, and masts. "Surge rate" is the rate of displacement along
> >>> an axis that is perpendicular to the local vertical axis and is
> >>> coplanar with the nominal forward motion direction of the platform.
> >>> Surge rate might not include changes to the ?at rest? position of
> >>> the platform with respect to the axis of displacement, which may
> >>> change over time. "Fore" indicates that positive values of surge
> >>> rate represent the platform moving forward as viewed by an observer
> >>> on top of the platform facing forward.
> >>>
> >>> platform_surge_rate_aft: Platform is a structure or vehicle that
> >>> serves as a base for mounting sensors. Platforms include, but are
> >>> not limited to, satellites, aeroplanes, ships, buoys, ground
> >>> stations, and masts. "Surge rate" is the rate of displacement along
> >>> an axis that is perpendicular to the local vertical axis and is
> >>> coplanar with the nominal forward motion direction of the platform.
> >>> Surge rate might not include changes to the ?at rest? position of
> >>> the platform with respect to the axis of displacement, which may
> >>> change over time. "Aft" indicates that positive values of surge rate
> >>> represent the platform moving backward as viewed by an observer on
> >>> top of the platform facing forward.
> >>>
> >>> platform_sway_port: Platform is a structure or vehicle that serves
> >>> as a base for mounting sensors. Platforms include, but are not
> >>> limited to, satellites, aeroplanes, ships, buoys, ground stations,
> >>> and masts. Sway is a displacement along an axis that is
> >>> perpendicular to both the local vertical axis and the nominal
> >>> forward motion direction of the platform. Sway is relative to the
> >>> ?at rest? position of the platform with respect to the axis of
> >>> displacement. The ?at rest? position of the platform may change over
> >>> time. "Port" indicates that positive values of sway represent the
> >>> platform moving left as viewed by an observer on top of the platform
> >>> facing forward.
> >>>
> >>> platform_sway_starboard: Platform is a structure or vehicle that
> >>> serves as a base for mounting sensors. Platforms include, but are
> >>> not limited to, satellites, aeroplanes, ships, buoys, ground
> >>> stations, and masts. Sway is a displacement along an axis that is
> >>> perpendicular to both the local vertical axis and the nominal
> >>> forward motion direction of the platform. Sway is relative to the
> >>> ?at rest? position of the platform with respect to the axis of
> >>> displacement. The ?at rest? position of the platform may change over
> >>> time. "Starboard" indicates that positive values of sway represent
> >>> the platform moving right as viewed by an observer on top of the
> >>> platform facing forward.
> >>>
> >>> platform_sway_rate_port: Platform is a structure or vehicle that
> >>> serves as a base for mounting sensors. Platforms include, but are
> >>> not limited to, satellites, aeroplanes, ships, buoys, ground
> >>> stations, and masts. "Sway rate" is the rate of displacement along
> >>> an axis that is perpendicular to both the local vertical axis and
> >>> the nominal forward motion direction of the platform. Sway rate may
> >>> not include changes to the ?at rest? position of the platform with
> >>> respect to the axis of displacement, which may change over time.
> >>> "Port" indicates that positive values of sway rate represent the
> >>> platform moving left as viewed by an observer on top of the platform
> >>> facing forward.
> >>>
> >>> platform_sway_rate_starboard: Platform is a structure or vehicle
> >>> that serves as a base for mounting sensors. Platforms include, but
> >>> are not limited to, satellites, aeroplanes, ships, buoys, ground
> >>> stations, and masts. "Sway rate" is a displacement along an axis
> >>> that is perpendicular to both the local vertical axis and the
> >>> nominal forward motion direction of the platform. Sway rate may not
> >>> include changes to the ?at rest? position of the platform with
> >>> respect to the axis of displacement, which may change over time.
> >>> "Starboard" indicates that positive values of sway rate represent
> >>> the platform moving right as viewed by an observer on top of the
> >>> platform facing forward.
> >>>
> >>> platform_heave_up: Platform is a structure or vehicle that serves as
> >>> a base for mounting sensors. Platforms include, but are not limited
> >>> to, satellites, aeroplanes, ships, buoys, ground stations, and
> >>> masts. Heave is a displacement along the local vertical axis. Heave
> >>> is relative to the ?at rest? position of the platform with respect
> >>> to the axis of displacement. The ?at rest? position of the platform
> >>> may change over time. "Up" indicates that positive values of heave
> >>> represent the platform moving up as viewed by an observer on top of
> >>> the platform facing forward.
> >>>
> >>> platform_heave_down: Platform is a structure or vehicle that serves
> >>> as a base for mounting sensors. Platforms include, but are not
> >>> limited to, satellites, aeroplanes, ships, buoys, ground stations,
> >>> and masts. Heave is a displacement along the local vertical axis.
> >>> Heave is relative to the ?at rest? position of the platform with
> >>> respect to the axis of displacement. The ?at rest? position of the
> >>> platform may change over time. "Down" indicates that positive values
> >>> of heave represent the platform moving down as viewed by an observer
> >>> on top of the platform facing forward.
> >>>
> >>> platform_heave_rate_up: Platform is a structure or vehicle that
> >>> serves as a base for mounting sensors. Platforms include, but are
> >>> not limited to, satellites, aeroplanes, ships, buoys, ground
> >>> stations, and masts. "Heave rate" is the rate of displacement along
> >>> the local vertical axis. Heave rate may not include changes to the
> >>> ?at rest? position of the platform with respect to the axis of
> >>> displacement, which may change over time. "Up" indicates that
> >>> positive values of heave rate represent the platform moving up as
> >>> viewed by an observer on top of the platform facing forward.
> >>>
> >>> platform_heave_rate_down: Platform is a structure or vehicle that
> >>> serves as a base for mounting sensors. Platforms include, but are
> >>> not limited to, satellites, aeroplanes, ships, buoys, ground
> >>> stations, and masts. "Heave rate" is the rate of displacement along
> >>> the local vertical axis. Heave rate may not include changes to the
> >>> ?at rest? position of the platform with respect to the axis of
> >>> displacement, which may change over time. "Down" indicates that
> >>> positive values of heave rate represent the platform moving down as
> >>> viewed by an observer on top of the platform facing forward.
> >>>
> >>> platform_course: Platform is a structure or vehicle that serves as a
> >>> base for mounting sensors. Platforms include, but are not limited
> >>> to, satellites, aeroplanes, ships, buoys, ground stations, and
> >>> masts. Course is the clockwise angle with respect to North of the
> >>> nominal forward motion direction of the platform.
> >>>
> >>> platform_orientation: Platform is a structure or vehicle that serves
> >>> as a base for mounting sensors. Platforms include, but are not
> >>> limited to, satellites, aeroplanes, ships, buoys, ground stations,
> >>> and masts. Orientation is the clockwise angle with respect to North
> >>> of the longitudinal (front-to-back) axis of the platform, which may
> >>> be different than the platform course (see platform_course).
> >>>
> >>>
> >>> On 9/11/18 12:13 PM, Lowry, Roy K. wrote:
> >>>>
> >>>> Dear Nan and Jim,
> >>>>
> >>>>
> >>>> It was me, on my own volition,?who raised concerns about the use of
> >>>> nautical terms to try and make the concepts domain-independent.
> >>>> However,?'port' is such an elegant way of saying 'left when facing
> >>>> forward' that I don't think we should resist it. Saw a nice
> >>>> definition for port ?- 'The side of a platform?that is on the left
> >>>> when one is facing forward.'
> >>>>
> >>>>
> >>>> Cheers, Roy.
> >>>>
> >>>>
> >>>> I have now retired but will continue to be active through an
> >>>> Emeritus Fellowship using this e-mail address.
> >>>>
> >>>>
> >>>>
> >>>>
> ------------------------------------------------------------------------
> >>>>
> >>>> *From:* CF-metadata <cf-metadata-bounces at cgd.ucar.edu> on behalf of
> >>>> Jim Biard <jbiard at cicsnc.org>
> >>>> *Sent:* 11 September 2018 16:37
> >>>> *To:* cf-metadata at cgd.ucar.edu
> >>>> *Subject:* Re: [CF-metadata] Platform Heave
> >>>>
> >>>> Nan,
> >>>>
> >>>> That was my concern. As I have thought about it, we can make it
> >>>> clear in the definition text. I'll generate those later this week.
> >>>>
> >>>> Jim
> >>>>
> >>>>
> >>>> On 9/11/18 10:53 AM, Nan Galbraith wrote:
> >>>>> I agree completely. Thanks to all for keeping at it with this topic.
> >>>>>
> >>>>> ?* platform_roll_starboard_down
> >>>>> ?* platform_yaw_fore_starboard
> >>>>> ?* platform_pitch_fore_up
> >>>>> ?* platform_surge_fore
> >>>>> ?* platform_sway _port
> >>>>> ?* platform_heave_up
> >>>>>
> >>>>> There was some concern expressed about using port and starboard,
> >>>>> because
> >>>>> satellite folks don't normally use those terms. I was unable to
> >>>>> figure out exactly
> >>>>> who raised this point, the thread is long and sometimes my mail
> >>>>> client makes the
> >>>>> sender of each message a little obscure.
> >>>>>
> >>>>> I'm assuming even satellites have a 'front' - ADCPs don't, really,
> >>>>> except by some
> >>>>> obscure convention set by the vendors - so presumably people will
> >>>>> be able to figure
> >>>>> out which side is which, and these terms will be OK.
> >>>>>
> >>>>> - Nan
> >>>>>
> >>>>>
> >>>>> On 9/7/18 4:07 AM, Lowry, Roy K. wrote:
> >>>>>>
> >>>>>> Good point,
> >>>>>>
> >>>>>>
> >>>>>> So you'd prefer platform_roll_starboard_down and so on?
> >>>>>>
> >>>>>>
> >>>>>> Cheers, Roy.
> >>>>>>
> >>>>>>
> >>>>>>
> ------------------------------------------------------------------------
> >>>>>> *From:* John Graybeal <jbgraybeal at mindspring.com>
> >>>>>> <mailto:jbgraybeal at mindspring.com>
> >>>>>> *Sent:* 07 September 2018 03:29
> >>>>>> *Subject:* Re: [CF-metadata] Platform Heave
> >>>>>> Sorry if I missed a point, but joining the motion to platform_
> >>>>>> will be much more findable. Platform roll for example is a really
> >>>>>> common expression.
> >>>>>>
> >>>>>> John
> >>>>>>
> >>>>>> On Sep 6, 2018, at 08:22, Lowry, Roy K. <rkl at bodc.ac.uk
> >>>>>> <mailto:rkl at bodc.ac.uk> <mailto:rkl at bodc.ac.uk>
> >>>>>> <mailto:rkl at bodc.ac.uk>> wrote:
> >>>>>>
> >>>>>>> Dear Jim,
> >>>>>>>
> >>>>>>>
> >>>>>>> Looking good to me.
> >>>>>>>
> >>>>>>>
> >>>>>>> Cheers, Roy.
> >>>>>>>
> >>>>>>>
> >>>>>>>
> ------------------------------------------------------------------------
> >>>>>>> *From:* CF-metadata <cf-metadata-bounces at cgd.ucar.edu
> >>>>>>> <mailto:cf-metadata-bounces at cgd.ucar.edu>
> >>>>>>> <mailto:cf-metadata-bounces at cgd.ucar.edu>
> >>>>>>> <mailto:cf-metadata-bounces at cgd.ucar.edu>> on behalf of Jim
> >>>>>>> Biard <jbiard at cicsnc.org <mailto:jbiard at cicsnc.org>
> >>>>>>> <mailto:jbiard at cicsnc.org> <mailto:jbiard at cicsnc.org>>
> >>>>>>> *Sent:* 05 September 2018 17:38
> >>>>>>> *Subject:* Re: [CF-metadata] Platform Heave
> >>>>>>>
> >>>>>>> Roy, Jonathan,
> >>>>>>>
> >>>>>>> I expect that surge, sway, and heave may well not have any
> >>>>>>> "alternate direction" representations in the wild, but I recall
> >>>>>>> that we found that the same is not true of pitch, roll, and yaw.
> >>>>>>>
> >>>>>>> Should we define the "canonical" set in such a fashion that the
> >>>>>>> sign convention is explicit and wait for people to request the
> >>>>>>> others?
> >>>>>>>
> >>>>>>> I guess that would be:
> >>>>>>>
> >>>>>>> ? * platform_starboard_down_roll
> >>>>>>> ? * platform_fore_starboard_yaw
> >>>>>>> ? * platform_fore_up_pitch
> >>>>>>> ? * platform_fore_surge
> >>>>>>> ? * platform_port_sway
> >>>>>>> ? * platform_up_heave
> >>>>>>>
> >>>>>>> Is that what we want?
> >>>>>>>
> >>>>>>> Grace and peace,
> >>>>>>>
> >>>>>>> Jim
> >>>>>>>
> >>>>>>> On 9/5/18 12:10 PM, Jonathan Gregory wrote:
> >>>>>>>>
> >>>>>>>> Dear Roy OK, yes. I agree with that too! We should not provide
> >>>>>>>> standard names for there is no use case yet. However, it's a
> >>>>>>>> good idea for foresee how this may be done, so that a neat
> >>>>>>>> solution is readily available when the day comes. Best wishes
> >>>>>>>> and thanks Jonathan On Wed, Sep 05, 2018 at 04:07:26PM +0000,
> >>>>>>>> Lowry, Roy K. wrote:
> >>>>>>>>>
> >>>>>>>>> Date: Wed, 5 Sep 2018 16:07:26 +0000 From: "Lowry, Roy K."
> >>>>>>>>> <rkl at bodc.ac.uk> <mailto:rkl at bodc.ac.uk>
> >>>>>>>>> <mailto:rkl at bodc.ac.uk> <mailto:rkl at bodc.ac.uk> Subject: Re:
> >>>>>>>>> [CF-metadata] Platform Heave Dear Jonathan, This isn't a
> >>>>>>>>> desire to mandate, it's just an attempt to prevent the
> >>>>>>>>> creation of six unnecessary Standard Names for sign
> >>>>>>>>> conventions based on my knowledge and researches of
> >>>>>>>>> oceanographic data that don't exist. Should anybody come up
> >>>>>>>>> with a single example of the opposite sign convention in
> >>>>>>>>> heave/sway/surge from any other domain then the additional
> >>>>>>>>> Standard Names will obviously need setting up. Anybody know of
> >>>>>>>>> any??? It also goes without saying the 'normal' conventions
> >>>>>>>>> should leave the door open - for example 'upward heave' leaves
> >>>>>>>>> the door open for a future 'downward heave'. This follows
> >>>>>>>>> another principle of CF Standard Names which is that Standard
> >>>>>>>>> Names should only set up when there is a demonstrable use case
> >>>>>>>>> and not just in case a use case arises. Cheers, Roy. From:
> >>>>>>>>> CF-metadata <cf-metadata-bounces at cgd.ucar.edu>
> >>>>>>>>> <mailto:cf-metadata-bounces at cgd.ucar.edu>
> >>>>>>>>> <mailto:cf-metadata-bounces at cgd.ucar.edu>
> >>>>>>>>> <mailto:cf-metadata-bounces at cgd.ucar.edu> on behalf of
> >>>>>>>>> Jonathan Gregory <j.m.gregory at reading.ac.uk>
> >>>>>>>>> <mailto:j.m.gregory at reading.ac.uk>
> >>>>>>>>> <mailto:j.m.gregory at reading.ac.uk>
> >>>>>>>>> <mailto:j.m.gregory at reading.ac.uk> Sent: 05 September 2018 16:26
> >>>>>>>>> Subject: Re: [CF-metadata] Platform Heave Dear Jim and Roy In
> >>>>>>>>> general, we want CF to be able to describe the datasets that
> >>>>>>>>> users want to describe, rather than mandating particular
> >>>>>>>>> choices. Projects that use CF can do that, of course, like
> >>>>>>>>> CMIP6 does, which prescribes the standard_names of the
> >>>>>>>>> quantities to be submitted. Best wishes Jonathan
> >>>>>>>>>>
> >>>>>>>>>> Date: Wed, 5 Sep 2018 09:32:37 -0400 From: Jim Biard
> >>>>>>>>>> <jbiard at cicsnc.org> <mailto:jbiard at cicsnc.org>
> >>>>>>>>>> <mailto:jbiard at cicsnc.org> <mailto:jbiard at cicsnc.org>
> >>>>>>>>>> Subject: Re: [CF-metadata] Platform Heave
> >>>>>>>>>> Roy, Good point! However (of course there has to be a
> >>>>>>>>>> 'but'!), are we OK with forcing people to modify their data
> >>>>>>>>>> to match our convention? Are there other situations where a
> >>>>>>>>>> standard name requires a certain representation? The existing
> >>>>>>>>>> datasets that people have mentioned are history, but they are
> >>>>>>>>>> also indicative of different sign conventions out there "in
> >>>>>>>>>> the wild". Grace and peace, Jim On 9/5/18 4:22 AM, Lowry, Roy
> >>>>>>>>>> K. wrote:
> >>>>>>>>>>>
> >>>>>>>>>>> Dear Jim, I think maybe you're doing more work than
> >>>>>>>>>>> necessary. I see the work falling into three parts. 1)
> >>>>>>>>>>> Revision of the definitions of heave/heave rate that are
> >>>>>>>>>>> part of a new Standard Name that has yet to be accepted. 2)
> >>>>>>>>>>> Creation of new Standard Names for Ken for sway/sway rate
> >>>>>>>>>>> and surge/surge rate 3) Upgrade to the definitions of the
> >>>>>>>>>>> existing Standard Names for pitch, roll and yaw. How about
> >>>>>>>>>>> hard-wiring direction conventions for cases (1) and (2) -
> >>>>>>>>>>> heave positive up, surge positive forwards and sway to match
> >>>>>>>>>>> Ken's data sets? As these are new Standard Names they cannot
> >>>>>>>>>>> be out in the wild with the opposite direction convention.
> >>>>>>>>>>> We would then need to deprecate the three existing Standard
> >>>>>>>>>>> Names and replace them with six new ones. One other thought
> >>>>>>>>>>> that is occupying my mind is whether the rate parameters are
> >>>>>>>>>>> scalars or vectors? Any thoughts? Cheers, Roy. *From:*
> >>>>>>>>>>> CF-metadata <cf-metadata-bounces at cgd.ucar.edu>
> >>>>>>>>>>> <mailto:cf-metadata-bounces at cgd.ucar.edu>
> >>>>>>>>>>> <mailto:cf-metadata-bounces at cgd.ucar.edu>
> >>>>>>>>>>> <mailto:cf-metadata-bounces at cgd.ucar.edu> on behalf of Jim
> >>>>>>>>>>> Biard <jbiard at cicsnc.org> <mailto:jbiard at cicsnc.org>
> >>>>>>>>>>> <mailto:jbiard at cicsnc.org> <mailto:jbiard at cicsnc.org>
> >>>>>>>>>>> *Sent:* 04 September 2018 16:36 *Subject:* Re: [CF-metadata]
> >>>>>>>>>>> Platform Heave Jonathan, Two out of three of Nan's "most
> >>>>>>>>>>> intuitive" rotations (pitch and yaw) are clockwise rather
> >>>>>>>>>>> than anticlockwise if the unit vectors are X-fore, Y-port,
> >>>>>>>>>>> and Z-up, which form a right-hand coordinate system. This is
> >>>>>>>>>>> part of why you will see examples where the unit vectors are
> >>>>>>>>>>> defined as X-fore, Y-starboard, and Z-down. This orientation
> >>>>>>>>>>> of the unit vectors makes yaw to starboard, pitch up, and
> >>>>>>>>>>> roll starboard down all anticlockwise rotations, but it
> >>>>>>>>>>> points the Z unit vector down, which is, for most people,
> >>>>>>>>>>> rather counter-intuitive. And this is why we are trying to
> >>>>>>>>>>> define things in terms that don't require specification of
> >>>>>>>>>>> unit vector directions. I'm going to try to continue down
> >>>>>>>>>>> that path and avoid calling out clockwise/anticlockwise.
> >>>>>>>>>>> Grace and peace, Jim On 9/4/18 10:18 AM, Jonathan Gregory
> >>>>>>>>>>> wrote:
> >>>>>>>>>>>>
> >>>>>>>>>>>> Dear Jim
> >>>>>>>>>>>>>
> >>>>>>>>>>>>> If that's the general consensus, then we can go that
> >>>>>>>>>>>>> general direction. I'll prepare pairs of everything.
> >>>>>>>>>>>>
> >>>>>>>>>>>> Thank you for your flexibility.
> >>>>>>>>>>>>>
> >>>>>>>>>>>>> Regarding Nan's suggestions for names - I'm not a "ship
> >>>>>>>>>>>>> person" so starboard and port are unfamiliar terms that I
> >>>>>>>>>>>>> have to constantly check myself on. I dislike putting them
> >>>>>>>>>>>>> in the names. I don't see them in regular use in the
> >>>>>>>>>>>>> satellite domain. The same goes for bow as far as usage
> >>>>>>>>>>>>> outside of the ship domain. Airplanes have noses.
> >>>>>>>>>>>>> Satellites have ... I don't know if there is even a name,
> >>>>>>>>>>>>> as there is no need for a leading edge. I'll struggle to
> >>>>>>>>>>>>> find something, and then we can wrangle over it.
> >>>>>>>>>>>>
> >>>>>>>>>>>> I agree with you - it would be better to have something
> >>>>>>>>>>>> generic and self- explanatory, even if it diverges from
> >>>>>>>>>>>> familiar terminology.
> >>>>>>>>>>>>>
> >>>>>>>>>>>>> I think the "most intuitive" way to represent the angles -
> >>>>>>>>>>>>> and most consistent as well, in my view - is clockwise
> >>>>>>>>>>>>> rotations around the unit vectors. This makes positive yaw
> >>>>>>>>>>>>> to starboard, positive pitch nose up, and positive roll
> >>>>>>>>>>>>> starboard up. But we are talking about having both signs
> >>>>>>>>>>>>> represented in names, so I guess that is moot.
> >>>>>>>>>>>>
> >>>>>>>>>>>> I agree with this too. For describing polygonal bounds, we
> >>>>>>>>>>>> say that the vertices should be traversed anticlockwise as
> >>>>>>>>>>>> seen from above. That is a positive direction of rotation
> >>>>>>>>>>>> around the vertical axis, since longitude- latitude-upward
> >>>>>>>>>>>> is a right-handed coordinate system. I suppose this is the
> >>>>>>>>>>>> yaw rotation - but is that the opposite sign from yours?
> >>>>>>>>>>>> Best wishes Jonathan
> >>>>>>>>>>>>>
> >>>>>>>>>>>>> On 9/3/18 12:51 PM, Jonathan Gregory wrote:
> >>>>>>>>>>>>>>
> >>>>>>>>>>>>>> Dear Roy and Nan I agree that if there are existing names
> >>>>>>>>>>>>>> whose sign convention is undefined we can't
> >>>>>>>>>>>>>> retrospectively define it. I think those ones ought to be
> >>>>>>>>>>>>>> deprecated, though, in favour of new ones with signs
> >>>>>>>>>>>>>> indicated. Best wishes Jonathan ----- Forwarded message
> >>>>>>>>>>>>>> from Nan Galbraith<ngalbraith at whoi.edu>
> >>>>>>>>>>>>>> <mailto:ngalbraith at whoi.edu> <mailto:ngalbraith at whoi.edu>
> >>>>>>>>>>>>>> <mailto:ngalbraith at whoi.edu>-----
> >>>>>>>>>>>>>>>
> >>>>>>>>>>>>>>> Date: Sun, 02 Sep 2018 11:57:33 -0400
> >>>>>>>>>>>>>> From: Nan Galbraith<ngalbraith at whoi.edu>
> >>>>>>>>>>>>>> <mailto:ngalbraith at whoi.edu> <mailto:ngalbraith at whoi.edu>
> >>>>>>>>>>>>>> <mailto:ngalbraith at whoi.edu>
> >>>>>>>>>>>>>>> ?I second Roy's suggestion; existing names have
> >>>>>>>>>>>>>>> undefined directionality, and new names have explicit
> >>>>>>>>>>>>>>> directions. This seems like the only way to move
> >>>>>>>>>>>>>>> forward. If there's a difference of opinion on which
> >>>>>>>>>>>>>>> direction should be in the new name, we can easily
> >>>>>>>>>>>>>>> create a pair for each term. What would the explicit
> >>>>>>>>>>>>>>> names be? Some of the terms in the thread below use
> >>>>>>>>>>>>>>> 'right' and 'left' where 'port' and 'starboard' might be
> >>>>>>>>>>>>>>> more clear, since, as Roy points out, left and right can
> >>>>>>>>>>>>>>> be taken as 'looking forwards from the platform or
> >>>>>>>>>>>>>>> looking at the front of the platform.' I also agree that
> >>>>>>>>>>>>>>> these are the most intuitive way to represent these
> >>>>>>>>>>>>>>> angles/motions:
> >>>>>>>>>>>>>>>>
> >>>>>>>>>>>>>>>> heave positive up pitch positive bow up yaw positive to
> >>>>>>>>>>>>>>>> starboard roll positive starboard side down
> >>>>>>>>>>>>>>>
> >>>>>>>>>>>>>>> Would the names be something like heave_up,
> >>>>>>>>>>>>>>> pitch_bow_up, yaw_to_starboard, and roll_to_starboard?
> >>>>>>>>>>>>>>> We do need to differentiate these from the exiting
> >>>>>>>>>>>>>>> names. Regards - Nan Quoting "Lowry, Roy
> >>>>>>>>>>>>>>> K."<rkl at bodc.ac.uk> <mailto:rkl at bodc.ac.uk>
> >>>>>>>>>>>>>>> <mailto:rkl at bodc.ac.uk> <mailto:rkl at bodc.ac.uk>
> >>>>>>>>>>>>>>> <mailto:rkl at bodc.ac.uk> <mailto:rkl at bodc.ac.uk>
> >>>>>>>>>>>>>>> <mailto:rkl at bodc.ac.uk> <mailto:rkl at bodc.ac.uk>:
> >>>>>>>>>>>>>>>>
> >>>>>>>>>>>>>>>> Dear Jim, From my researches into existing
> >>>>>>>>>>>>>>>> oceanographic data sets (SeaDataCloud holdings plus EU
> >>>>>>>>>>>>>>>> glider data projects), covering heave, pitch, roll and
> >>>>>>>>>>>>>>>> yaw. I haven't discovered a single deviation from the
> >>>>>>>>>>>>>>>> conventions:
> >>>>>>>>>>>>>>>> heave positive up Pitch positive bow/nose up yaw
> >>>>>>>>>>>>>>>> positive to starboard roll starboard side down I have
> >>>>>>>>>>>>>>>> yet to find any data sets, other than those described
> >>>>>>>>>>>>>>>> by Ken in these discussions, in my searches containing
> >>>>>>>>>>>>>>>> surge or sway. The only ambiguity I have found in the
> >>>>>>>>>>>>>>>> wider domain of Google is where the concept of
> >>>>>>>>>>>>>>>> 'positive clockwise' has been used without specifying
> >>>>>>>>>>>>>>>> whether the observer is looking forwards from the
> >>>>>>>>>>>>>>>> platform or looking at the front of the platform. This
> >>>>>>>>>>>>>>>> isn't helped by the multitude of bidirectional vectors
> >>>>>>>>>>>>>>>> (arrows at each end) in illustrative diagrams. Might
> >>>>>>>>>>>>>>>> our lives be made easier if we adopted a set of
> >>>>>>>>>>>>>>>> conventions, state them explicitly in the Standard
> >>>>>>>>>>>>>>>> Names as Jonathan suggests leaving room in the unlikely
> >>>>>>>>>>>>>>>> - in my view at least - event of Standard Names for the
> >>>>>>>>>>>>>>>> opposite convention being required? Cheers, Roy. From:
> >>>>>>>>>>>>>>>> CF-metadata on behalf of Jim Biard<jbiard at cicsnc.org>
> >>>>>>>>>>>>>>>> <mailto:jbiard at cicsnc.org> <mailto:jbiard at cicsnc.org>
> >>>>>>>>>>>>>>>> <mailto:jbiard at cicsnc.org>
> >>>>>>>>>>>>>>>> Sent: 31 August 2018 14:38 ?Jonathan, That's only part
> >>>>>>>>>>>>>>>> of the issue. Here are the issues as I see them. *
> >>>>>>>>>>>>>>>> There is no single sign convention being followed in
> >>>>>>>>>>>>>>>> existing datasets "in the wild". * There is a
> >>>>>>>>>>>>>>>> long-standing convention for vertical coordinates using
> >>>>>>>>>>>>>>>> the attribute positive rather than having pairs of
> >>>>>>>>>>>>>>>> standard names for height_positive_up,
> >>>>>>>>>>>>>>>> height_positive_down, etc. The suggested solution is
> >>>>>>>>>>>>>>>> corollary, and the positive attribute could be used
> >>>>>>>>>>>>>>>> instead of adding a new attribute named direction with
> >>>>>>>>>>>>>>>> a suitable expansion of possible valid values. * In
> >>>>>>>>>>>>>>>> order to cover all bases, we'd need three versions for
> >>>>>>>>>>>>>>>> each standard name (e.g. - platform_roll,
> >>>>>>>>>>>>>>>> platform_roll_clockwise, platform_roll_anticlockwise -
> >>>>>>>>>>>>>>>> or similar names) * Having three different versions of
> >>>>>>>>>>>>>>>> each standard name will lead to new possibilities for
> >>>>>>>>>>>>>>>> getting things wrong by picking the wrong version. *
> >>>>>>>>>>>>>>>> Semantically, there is only one concept in each case.
> >>>>>>>>>>>>>>>> If I am searching for roll variables and I have
> >>>>>>>>>>>>>>>> multiple names that mean roll, I must expand my search
> >>>>>>>>>>>>>>>> to include all variants. This is a small example, but
> >>>>>>>>>>>>>>>> there are other examples of this problem that are
> >>>>>>>>>>>>>>>> definitely not trivial and defeat one of the goals for
> >>>>>>>>>>>>>>>> using standard names - being able to find like
> >>>>>>>>>>>>>>>> quantities across datasets, particularly using
> >>>>>>>>>>>>>>>> automated techniques rather than human eyes. Grace and
> >>>>>>>>>>>>>>>> peace, Jim On 8/31/18 8:52 AM, Jonathan Gregory wrote:
> >>>>>>>>>>>>>>>> Dear all I haven't been following this discussion, so
> >>>>>>>>>>>>>>>> please excuse me if I've missed the point. I think you
> >>>>>>>>>>>>>>>> are suggesting introducing a new attribute to indicate
> >>>>>>>>>>>>>>>> the positive sense of various new quantities for
> >>>>>>>>>>>>>>>> platform orientation - is that right? To do that would
> >>>>>>>>>>>>>>>> not be consistent with other standard names, which
> >>>>>>>>>>>>>>>> (where relevant) all have the positive sense indicate
> >>>>>>>>>>>>>>>> in the standard name itself. That's why there are many
> >>>>>>>>>>>>>>>> pairs of standard names for upward/downward, in
> >>>>>>>>>>>>>>>> particular. The reason for doing this is to make it
> >>>>>>>>>>>>>>>> impossible to name the quantity without indicating its
> >>>>>>>>>>>>>>>> sign convention, whereas a separate attribute can be
> >>>>>>>>>>>>>>>> omitted, and probably sometimes will. It also opens new
> >>>>>>>>>>>>>>>> possibilities for getting things wrong, by putting
> >>>>>>>>>>>>>>>> illegal values in it. Therefore I would argue for the
> >>>>>>>>>>>>>>>> same approach here, both because I think it's less
> >>>>>>>>>>>>>>>> error-prone, and for consistency with other CF standard
> >>>>>>>>>>>>>>>> names. I'm sure the objection occurs to you that this
> >>>>>>>>>>>>>>>> means more standard names. That's true, but it's only
> >>>>>>>>>>>>>>>> twice as many, I believe, since each of the quantities
> >>>>>>>>>>>>>>>> has only two possible senses.
> >>>>>>>>>>>>>>> Best wishes Jonathan
> >>>>>>>>>>>>>>>> ----- Forwarded message from Kenneth Kehoe
> >>>>>>>>>>>>>>>> <kkehoe at ou.edu> <mailto:kkehoe at ou.edu>
> >>>>>>>>>>>>>>>> <mailto:kkehoe at ou.edu> <mailto:kkehoe at ou.edu>
> >>>>>>>>>>>>>>>> <mailto:kkehoe at ou.edu> <mailto:kkehoe at ou.edu>
> >>>>>>>>>>>>>>>> <mailto:kkehoe at ou.edu> <mailto:kkehoe at ou.edu>
> >>>>>>>>>>>>>>>> Date: Thu, 30 Aug 2018 12:05:44 -0600
> >>>>>>>>>>>>>>>> From: Kenneth Kehoe<kkehoe at ou.edu>
> >>>>>>>>>>>>>>>> <mailto:kkehoe at ou.edu> <mailto:kkehoe at ou.edu>
> >>>>>>>>>>>>>>>> <mailto:kkehoe at ou.edu>
> >>>>>>>>>>>>>>>> Subject: Re: [CF-metadata] Platform Heave
> >>>>>>>>>>>>>>>> I think we should keep things simple as Ethan suggests
> >>>>>>>>>>>>>>>> below. But since the proposed attribute "direction" is
> >>>>>>>>>>>>>>>> defined as indicating the positive direction we don't
> >>>>>>>>>>>>>>>> need to include the word positive. The terms would then
> >>>>>>>>>>>>>>>> be: roll: "right_side_up" and "right_side_down" pitch:
> >>>>>>>>>>>>>>>> "nose_up" and "nose_down" yaw: "nose_right" and
> >>>>>>>>>>>>>>>> "nose_left" surge: "forward" and "backward" sway:
> >>>>>>>>>>>>>>>> "left" and "right" heave: "up" and "down" It would be
> >>>>>>>>>>>>>>>> nice to be more explicit in the netCDF file and require
> >>>>>>>>>>>>>>>> less on the standard_name definition so I would suggest
> >>>>>>>>>>>>>>>> we use the original proposed attribute name of
> >>>>>>>>>>>>>>>> "positive_direction" with the above allowed values. Or
> >>>>>>>>>>>>>>>> if we don't want to add a new attribute we could use
> >>>>>>>>>>>>>>>> the existing "positive" attribute and expand its
> >>>>>>>>>>>>>>>> allowed use. I've proposed this in the past and it was
> >>>>>>>>>>>>>>>> decided to not expand the definition. I think the
> >>>>>>>>>>>>>>>> concern for not expanding positive was the requirement
> >>>>>>>>>>>>>>>> of only using that attribute on coordinate variables.
> >>>>>>>>>>>>>>>> For the coordinate variable the only allowable values
> >>>>>>>>>>>>>>>> are up and down. But for this use those values would
> >>>>>>>>>>>>>>>> only be attached to a variable, not a coordinate
> >>>>>>>>>>>>>>>> variable. Since we are creating an attribute to define
> >>>>>>>>>>>>>>>> the positive direction I would like to add radial
> >>>>>>>>>>>>>>>> definition of "toward" and "away". But I think we can
> >>>>>>>>>>>>>>>> simplify this a bit further. If we define the point of
> >>>>>>>>>>>>>>>> reference that is moving in the standard name then we
> >>>>>>>>>>>>>>>> don't need to put the point of reference in the
> >>>>>>>>>>>>>>>> positive (or direction or positive_direction)
> >>>>>>>>>>>>>>>> attribute. For example the pitch standard_name would
> >>>>>>>>>>>>>>>> indicate the location of reference of the nose. This
> >>>>>>>>>>>>>>>> would then reduce the list of possible options to:
> >>>>>>>>>>>>>>>> roll: "up" and "down" pitch: "up" and "down" yaw:
> >>>>>>>>>>>>>>>> "right" and "left" surge: "forward" and "backward"
> >>>>>>>>>>>>>>>> sway: "left" and "right" heave: "up" and "down" If we
> >>>>>>>>>>>>>>>> could use the current attribute of "positive" that has
> >>>>>>>>>>>>>>>> up and down already defined then we only need to to add
> >>>>>>>>>>>>>>>> "right", "left", "forward", "backward", "toward",
> >>>>>>>>>>>>>>>> "away". Easy! Ken On 2018-8-29 13:54, Ethan Davis
> >>>>>>>>>>>>>>>> wrote: Hey Jim, How about removing one layer of
> >>>>>>>>>>>>>>>> terminology by using your definitions for the allowed
> >>>>>>>>>>>>>>>> values of "direction": roll: "positive_right_side_up"
> >>>>>>>>>>>>>>>> and "positive_right_side_down". pitch:
> >>>>>>>>>>>>>>>> "positive_nose_up" and "positive_nose_down". yaw:
> >>>>>>>>>>>>>>>> "positive_nose_right" and "positive_nose_left". surge:
> >>>>>>>>>>>>>>>> "positive_forward" and "positive_backward". sway:
> >>>>>>>>>>>>>>>> "positive_left" and "positive_right". heave:
> >>>>>>>>>>>>>>>> "positive_up" and "positive_down". Cheers, Ethan On
> >>>>>>>>>>>>>>>> Wed, Aug 29, 2018 at 12:02 PM Jim Biard
> >>>>>>>>>>>>>>>> <jbiard at cicsnc.org <mailto:jbiard at cicsnc.org>
> >>>>>>>>>>>>>>>> <mailto:jbiard at cicsnc.org>
> >>>>>>>>>>>>>>>> <mailto:jbiard at cicsnc.org>>wrote: John, There are a
> >>>>>>>>>>>>>>>> variety of conventions for defining roll, pitch, and
> >>>>>>>>>>>>>>>> yaw out there. This is why we are avoiding a specific
> >>>>>>>>>>>>>>>> one. Others have searched existing datasets that are
> >>>>>>>>>>>>>>>> using earlier versions of these standard names (or not
> >>>>>>>>>>>>>>>> using standard names) and found that they don't all
> >>>>>>>>>>>>>>>> follow the same convention. Ethan, We purposely aren't
> >>>>>>>>>>>>>>>> answering that question directly because of the issue
> >>>>>>>>>>>>>>>> above. I believe that I have consistently followed the
> >>>>>>>>>>>>>>>> convention in which clockwise and anticlockwise are
> >>>>>>>>>>>>>>>> rotational directions around a unit vector facing the
> >>>>>>>>>>>>>>>> observer, where the X unit vector is in the nominally
> >>>>>>>>>>>>>>>> forward direction, the Z axis is in the local up
> >>>>>>>>>>>>>>>> direction, and the Y axis unit vector is "Z cross X",
> >>>>>>>>>>>>>>>> which forms a right-handed coordinate system. The terms
> >>>>>>>>>>>>>>>> are meaningful and accurate using that convention, but
> >>>>>>>>>>>>>>>> the names could be "alpha" and "beta" or "dog" and
> >>>>>>>>>>>>>>>> "cat" as long as they are used correctly. This whole
> >>>>>>>>>>>>>>>> topic is fraught with competing conventions, so we are
> >>>>>>>>>>>>>>>> attempting to avoid declaring that only one of them is
> >>>>>>>>>>>>>>>> valid, with it's corresponding requirement that
> >>>>>>>>>>>>>>>> everyone follow that one sign convention. In fact, we
> >>>>>>>>>>>>>>>> could reword things to remove naming the axes X, Y, and
> >>>>>>>>>>>>>>>> Z, and perhaps we should. I know of satellite platforms
> >>>>>>>>>>>>>>>> that define their Y axis unit vector as pointing
> >>>>>>>>>>>>>>>> forward and the Z axis unit vector as pointing down.
> >>>>>>>>>>>>>>>> Thoughts? Grace and peace, Jim On 8/29/18 1:32 PM, John
> >>>>>>>>>>>>>>>> Helly wrote: Perhaps one should refer to the discipline
> >>>>>>>>>>>>>>>> of hydrostatics for help with this? This paper, pulled
> >>>>>>>>>>>>>>>> from a quick search, has a diagram referencing the
> >>>>>>>>>>>>>>>> platforms' frame of reference with respect to its
> >>>>>>>>>>>>>>>> center of gravity. Sorry if this comment is retrograd...
> >>>>>>>>>>>>>>>> J. On 8/29/18 10:09, Ethan Davis wrote: Hi Jim, all,
> >>>>>>>>>>>>>>>> I'm a bit confused by the "clockwise" and
> >>>>>>>>>>>>>>>> "anticlockwise". You mention the orientation of the
> >>>>>>>>>>>>>>>> observer but not the location/orientation of the clock.
> >>>>>>>>>>>>>>>> My assumptions (not sure why) for the clock: for roll,
> >>>>>>>>>>>>>>>> the observer (who is facing forward) would be facing
> >>>>>>>>>>>>>>>> the clock; for pitch, the observer would look right to
> >>>>>>>>>>>>>>>> see the clock; and for yaw, the observer would look
> >>>>>>>>>>>>>>>> down to see the clock. That works for your definitions
> >>>>>>>>>>>>>>>> of pitch and yaw, but is backwards for roll. Does
> >>>>>>>>>>>>>>>> "clockwise" add, in some way, another degree of freedom
> >>>>>>>>>>>>>>>> to the definition? Does that degree of freedom need to
> >>>>>>>>>>>>>>>> be nailed down in the definitions? Or other terms used
> >>>>>>>>>>>>>>>> instead? I don't have any good suggestions other than
> >>>>>>>>>>>>>>>> "positive" and "negative". Cheers, Ethan On Wed, Aug
> >>>>>>>>>>>>>>>> 29, 2018 at 9:03 AM Jim Biard<jbiard at cicsnc.org>
> >>>>>>>>>>>>>>>> <mailto:jbiard at cicsnc.org> <mailto:jbiard at cicsnc.org>
> >>>>>>>>>>>>>>>> <mailto:jbiard at cicsnc.org> wrote: Hi. I've finally
> >>>>>>>>>>>>>>>> gotten back to this topic! The definitions below call
> >>>>>>>>>>>>>>>> out an attribute named "direction" that is used to
> >>>>>>>>>>>>>>>> specify the direction for positive values of the
> >>>>>>>>>>>>>>>> different quantities. We may need to add a definition
> >>>>>>>>>>>>>>>> for the attribute to the Conventions. The values and
> >>>>>>>>>>>>>>>> meanings for the direction attribute are: roll:
> >>>>>>>>>>>>>>>> "clockwise" for positive right side up and
> >>>>>>>>>>>>>>>> "anticlockwise" for positive right side down. pitch:
> >>>>>>>>>>>>>>>> "clockwise" for positive nose up and "anticlockwise"
> >>>>>>>>>>>>>>>> for positive nose down. yaw: "clockwise" for positive
> >>>>>>>>>>>>>>>> nose right and "anticlockwise" for positive nose left.
> >>>>>>>>>>>>>>>> surge: "positive" for positive forward and "negative"
> >>>>>>>>>>>>>>>> for positive backward. sway: "positive" for positive
> >>>>>>>>>>>>>>>> left and "negative" for positive right. heave:
> >>>>>>>>>>>>>>>> "positive" for positive up and "negative" for positive
> >>>>>>>>>>>>>>>> down. And here are the standard name definitions:
> >>>>>>>>>>>>>>>> platform_roll: Platform is a structure or vehicle that
> >>>>>>>>>>>>>>>> serves as a base for mounting sensors. Platforms
> >>>>>>>>>>>>>>>> include, but are not limited to, satellites,
> >>>>>>>>>>>>>>>> aeroplanes, ships, buoys, ground stations, and masts.
> >>>>>>>>>>>>>>>> Roll is a rotation about an axis (the X axis) that is
> >>>>>>>>>>>>>>>> perpendicular to the local vertical axis (the Z axis)
> >>>>>>>>>>>>>>>> and is coplanar with the nominal forward motion
> >>>>>>>>>>>>>>>> direction of the platform. Roll is relative to the ?at
> >>>>>>>>>>>>>>>> rest? rotation of the platform with respect to the X
> >>>>>>>>>>>>>>>> axis. The ?at rest? rotation of the platform may change
> >>>>>>>>>>>>>>>> over time. The direction for positive values of roll is
> >>>>>>>>>>>>>>>> specified by an attribute named direction. The value of
> >>>>>>>>>>>>>>>> the direction attribute is "clockwise" if positive
> >>>>>>>>>>>>>>>> values of roll represent the right side of the platform
> >>>>>>>>>>>>>>>> rising as viewed by an observer on top of the platform
> >>>>>>>>>>>>>>>> facing forward. The value of the direction attribute is
> >>>>>>>>>>>>>>>> "anticlockwise" if positive values of roll represent
> >>>>>>>>>>>>>>>> the right side of the platform falling. The
> >>>>>>>>>>>>>>>> directionality of roll values is unspecified if no
> >>>>>>>>>>>>>>>> direction attribute is present. platform_pitch:
> >>>>>>>>>>>>>>>> Platform is a structure or vehicle that serves as a
> >>>>>>>>>>>>>>>> base for mounting sensors. Platforms include, but are
> >>>>>>>>>>>>>>>> not limited to, satellites, aeroplanes, ships, buoys,
> >>>>>>>>>>>>>>>> ground stations, and masts. Pitch is a rotation about
> >>>>>>>>>>>>>>>> an axis (the Y axis) that is perpendicular to both the
> >>>>>>>>>>>>>>>> local vertical axis (the Z axis) and the nominal
> >>>>>>>>>>>>>>>> forward motion direction of the platform. Pitch is
> >>>>>>>>>>>>>>>> relative to the ?at rest? rotation of the platform with
> >>>>>>>>>>>>>>>> respect to the Y axis. The ?at rest? rotation of the
> >>>>>>>>>>>>>>>> platform may change over time. The direction for
> >>>>>>>>>>>>>>>> positive values of pitch is specified by an attribute
> >>>>>>>>>>>>>>>> named direction. The value of the direction attribute
> >>>>>>>>>>>>>>>> is "clockwise" if positive values of pitch represent
> >>>>>>>>>>>>>>>> the front of the platform rising as viewed by an
> >>>>>>>>>>>>>>>> observer on top of the platform facing forward. The
> >>>>>>>>>>>>>>>> value of the direction attribute is "anticlockwise" if
> >>>>>>>>>>>>>>>> positive values of pitch represent the front of the
> >>>>>>>>>>>>>>>> platform falling. The directionality of pitch values is
> >>>>>>>>>>>>>>>> unspecified if no direction attribute is present.
> >>>>>>>>>>>>>>>> platform_yaw: Platform is a structure or vehicle that
> >>>>>>>>>>>>>>>> serves as a base for mounting sensors. Platforms
> >>>>>>>>>>>>>>>> include, but are not limited to, satellites,
> >>>>>>>>>>>>>>>> aeroplanes, ships, buoys, ground stations, and masts.
> >>>>>>>>>>>>>>>> Yaw is a rotation about the local vertical axis (the Z
> >>>>>>>>>>>>>>>> axis). Yaw is relative to the ?at rest? rotation of the
> >>>>>>>>>>>>>>>> platform with respect to the Z axis. The ?at rest?
> >>>>>>>>>>>>>>>> rotation of the platform may change over time. The
> >>>>>>>>>>>>>>>> direction for positive values of yaw is specified by an
> >>>>>>>>>>>>>>>> attribute named direction. The value of the direction
> >>>>>>>>>>>>>>>> attribute is "clockwise" if positive values of yaw
> >>>>>>>>>>>>>>>> represent the front of the platform moving to the right
> >>>>>>>>>>>>>>>> as viewed by an observer on top of the platform facing
> >>>>>>>>>>>>>>>> forward. The value of the direction attribute is
> >>>>>>>>>>>>>>>> "anticlockwise" if positive values of yaw represent the
> >>>>>>>>>>>>>>>> front of the platform moving to the left. The
> >>>>>>>>>>>>>>>> directionality of yaw values is unspecified if no
> >>>>>>>>>>>>>>>> direction attribute is present. platform_surge:
> >>>>>>>>>>>>>>>> Platform is a structure or vehicle that serves as a
> >>>>>>>>>>>>>>>> base for mounting sensors. Platforms include, but are
> >>>>>>>>>>>>>>>> not limited to, satellites, aeroplanes, ships, buoys,
> >>>>>>>>>>>>>>>> ground stations, and masts. Surge is a displacement
> >>>>>>>>>>>>>>>> along an axis (the X axis) that is perpendicular to the
> >>>>>>>>>>>>>>>> local vertical axis (the Z axis) and is coplanar with
> >>>>>>>>>>>>>>>> the nominal forward motion direction of the platform.
> >>>>>>>>>>>>>>>> Surge is relative to the ?at rest? position of the
> >>>>>>>>>>>>>>>> platform with respect to the X axis. The ?at rest?
> >>>>>>>>>>>>>>>> position of the platform may change over time. The
> >>>>>>>>>>>>>>>> direction for positive values of surge is specified by
> >>>>>>>>>>>>>>>> an attribute named direction. The value of the
> >>>>>>>>>>>>>>>> direction attribute is "positive" if positive values of
> >>>>>>>>>>>>>>>> surge represent the platform moving forward as viewed
> >>>>>>>>>>>>>>>> by an observer on top of the platform facing forward.
> >>>>>>>>>>>>>>>> The value of the direction attribute is "negative" if
> >>>>>>>>>>>>>>>> positive values of surge represent the platform moving
> >>>>>>>>>>>>>>>> backward. The directionality of surge values is
> >>>>>>>>>>>>>>>> unspecified if no direction attribute is present.
> >>>>>>>>>>>>>>>> platform_sway: Platform is a structure or vehicle that
> >>>>>>>>>>>>>>>> serves as a base for mounting sensors. Platforms
> >>>>>>>>>>>>>>>> include, but are not limited to, satellites,
> >>>>>>>>>>>>>>>> aeroplanes, ships, buoys, ground stations, and masts.
> >>>>>>>>>>>>>>>> Sway is a displacement along an axis (the Y axis) that
> >>>>>>>>>>>>>>>> is perpendicular to both the local vertical axis (the Z
> >>>>>>>>>>>>>>>> axis) and the nominal forward motion direction of the
> >>>>>>>>>>>>>>>> platform. Sway is relative to the ?at rest? position of
> >>>>>>>>>>>>>>>> the platform with respect to the Y axis. The ?at rest?
> >>>>>>>>>>>>>>>> position of the platform may change over time. The
> >>>>>>>>>>>>>>>> direction for positive values of sway is specified by
> >>>>>>>>>>>>>>>> an attribute named direction. The value of the
> >>>>>>>>>>>>>>>> direction attribute is "positive" if positive values of
> >>>>>>>>>>>>>>>> sway represent the platform moving left as viewed by an
> >>>>>>>>>>>>>>>> observer on top of the platform facing forward. The
> >>>>>>>>>>>>>>>> value of the direction attribute is "negative" if
> >>>>>>>>>>>>>>>> positive values of sway represent the platform moving
> >>>>>>>>>>>>>>>> right. The directionality of sway values is unspecified
> >>>>>>>>>>>>>>>> if no direction attribute is present. platform_heave:
> >>>>>>>>>>>>>>>> Platform is a structure or vehicle that serves as a
> >>>>>>>>>>>>>>>> base for mounting sensors. Platforms include, but are
> >>>>>>>>>>>>>>>> not limited to, satellites, aeroplanes, ships, buoys,
> >>>>>>>>>>>>>>>> ground stations, and masts. Heave is a displacement
> >>>>>>>>>>>>>>>> along the local vertical axis (the Z axis). Heave is
> >>>>>>>>>>>>>>>> relative to the ?at rest? position of the platform with
> >>>>>>>>>>>>>>>> respect to the Z axis. The ?at rest? position of the
> >>>>>>>>>>>>>>>> platform may change over time. The direction for
> >>>>>>>>>>>>>>>> positive values of heave is specified by an attribute
> >>>>>>>>>>>>>>>> named direction. The value of the direction attribute
> >>>>>>>>>>>>>>>> is "positive" if positive values of heave represent the
> >>>>>>>>>>>>>>>> platform moving up as viewed by an observer on top of
> >>>>>>>>>>>>>>>> the platform facing forward. The value of the direction
> >>>>>>>>>>>>>>>> attribute is "negative" if positive values of heave
> >>>>>>>>>>>>>>>> represent the platform moving down. The directionality
> >>>>>>>>>>>>>>>> of heave values is unspecified if no direction
> >>>>>>>>>>>>>>>> attribute is present. platform_course: Platform is a
> >>>>>>>>>>>>>>>> structure or vehicle that serves as a base for mounting
> >>>>>>>>>>>>>>>> sensors. Platforms include, but are not limited to,
> >>>>>>>>>>>>>>>> satellites, aeroplanes, ships, buoys, ground stations,
> >>>>>>>>>>>>>>>> and masts. Course is the clockwise angle with respect
> >>>>>>>>>>>>>>>> to North of the nominal forward motion direction of the
> >>>>>>>>>>>>>>>> platform. platform_orientation: Platform is a structure
> >>>>>>>>>>>>>>>> or vehicle that serves as a base for mounting sensors.
> >>>>>>>>>>>>>>>> Platforms include, but are not limited to, satellites,
> >>>>>>>>>>>>>>>> aeroplanes, ships, buoys, ground stations, and masts.
> >>>>>>>>>>>>>>>> Orientation is the clockwise angle with respect to
> >>>>>>>>>>>>>>>> North of the longitudinal (front-to-back) axis of the
> >>>>>>>>>>>>>>>> platform, which may be different than the platform
> >>>>>>>>>>>>>>>> course (see platform_course). platform_roll_rate:
> >>>>>>>>>>>>>>>> Platform is a structure or vehicle that serves as a
> >>>>>>>>>>>>>>>> base for mounting sensors. Platforms include, but are
> >>>>>>>>>>>>>>>> not limited to, satellites, aeroplanes, ships, buoys,
> >>>>>>>>>>>>>>>> ground stations, and masts. Roll rate is the rate of
> >>>>>>>>>>>>>>>> rotation about an axis (the X axis) that is
> >>>>>>>>>>>>>>>> perpendicular to the local vertical axis (the Z axis)
> >>>>>>>>>>>>>>>> and is coplanar with the nominal forward motion
> >>>>>>>>>>>>>>>> direction of the platform. Roll rate might not include
> >>>>>>>>>>>>>>>> changes in the ?at rest? rotation of the platform,
> >>>>>>>>>>>>>>>> which may change over time. The direction for positive
> >>>>>>>>>>>>>>>> values of roll rate is specified by an attribute named
> >>>>>>>>>>>>>>>> direction. The value of the direction attribute is
> >>>>>>>>>>>>>>>> "clockwise" if positive values of roll rate represent
> >>>>>>>>>>>>>>>> the right side of the platform rising as viewed by an
> >>>>>>>>>>>>>>>> observer on top of the platform facing forward. The
> >>>>>>>>>>>>>>>> value of the direction attribute is "anticlockwise" if
> >>>>>>>>>>>>>>>> positive values of roll rate represent the right side
> >>>>>>>>>>>>>>>> of the platform falling. The directionality of roll
> >>>>>>>>>>>>>>>> rate values is unspecified if no direction attribute is
> >>>>>>>>>>>>>>>> present. platform_pitch_rate: Platform is a structure
> >>>>>>>>>>>>>>>> or vehicle that serves as a base for mounting sensors.
> >>>>>>>>>>>>>>>> Platforms include, but are not limited to, satellites,
> >>>>>>>>>>>>>>>> aeroplanes, ships, buoys, ground stations, and masts.
> >>>>>>>>>>>>>>>> Pitch rate is the rate of rotation about an axis (the Y
> >>>>>>>>>>>>>>>> axis) that is perpendicular to both the local vertical
> >>>>>>>>>>>>>>>> axis (the Z axis) and the nominal forward motion
> >>>>>>>>>>>>>>>> direction of the platform. Pitch rate might not include
> >>>>>>>>>>>>>>>> changes in the ?at rest? rotation of the platform,
> >>>>>>>>>>>>>>>> which may change over time. The direction for positive
> >>>>>>>>>>>>>>>> values of pitch rate is specified by an attribute named
> >>>>>>>>>>>>>>>> direction. The value of the direction attribute is
> >>>>>>>>>>>>>>>> "clockwise" if positive values of pitch rate represent
> >>>>>>>>>>>>>>>> the front of the platform rising as viewed by an
> >>>>>>>>>>>>>>>> observer on top of the platform facing forward. The
> >>>>>>>>>>>>>>>> value of the direction attribute is "anticlockwise" if
> >>>>>>>>>>>>>>>> positive values of pitch rate represent the front of
> >>>>>>>>>>>>>>>> the platform falling. The directionality of pitch rate
> >>>>>>>>>>>>>>>> values is unspecified if no direction attribute is
> >>>>>>>>>>>>>>>> present. platform_yaw_rate: Platform is a structure or
> >>>>>>>>>>>>>>>> vehicle that serves as a base for mounting sensors.
> >>>>>>>>>>>>>>>> Platforms include, but are not limited to, satellites,
> >>>>>>>>>>>>>>>> aeroplanes, ships, buoys, ground stations, and masts.
> >>>>>>>>>>>>>>>> Yaw rate is the rate of rotation about the local
> >>>>>>>>>>>>>>>> vertical axis (the Z axis). Yaw rate might not include
> >>>>>>>>>>>>>>>> changes in the ?at rest? rotation of the platform,
> >>>>>>>>>>>>>>>> which may change over time. The direction for positive
> >>>>>>>>>>>>>>>> values of yaw rate is specified by an attribute named
> >>>>>>>>>>>>>>>> direction. The value of the direction attribute is
> >>>>>>>>>>>>>>>> "clockwise" if positive values of yaw rate represent
> >>>>>>>>>>>>>>>> the front of the platform moving to the right as viewed
> >>>>>>>>>>>>>>>> by an observer on top of the platform facing forward.
> >>>>>>>>>>>>>>>> The value of the direction attribute is "anticlockwise"
> >>>>>>>>>>>>>>>> if positive values of yaw rate represent the front of
> >>>>>>>>>>>>>>>> the platform moving to the left. The directionality of
> >>>>>>>>>>>>>>>> yaw rate values is unspecified if no direction
> >>>>>>>>>>>>>>>> attribute is present. platform_surge_rate: Platform is
> >>>>>>>>>>>>>>>> a structure or vehicle that serves as a base for
> >>>>>>>>>>>>>>>> mounting sensors. Platforms include, but are not
> >>>>>>>>>>>>>>>> limited to, satellites, aeroplanes, ships, buoys,
> >>>>>>>>>>>>>>>> ground stations, and masts. Surge rate is the rate of
> >>>>>>>>>>>>>>>> displacement along an axis (the X axis) that is
> >>>>>>>>>>>>>>>> perpendicular to the local vertical axis (the Z axis)
> >>>>>>>>>>>>>>>> and is coplanar with the nominal forward motion
> >>>>>>>>>>>>>>>> direction of the platform. Surge rate might not include
> >>>>>>>>>>>>>>>> changes in the ?at rest? position of the platform,
> >>>>>>>>>>>>>>>> which may change over time. The direction for positive
> >>>>>>>>>>>>>>>> values of surge rate is specified by an attribute named
> >>>>>>>>>>>>>>>> direction. The value of the direction attribute is
> >>>>>>>>>>>>>>>> "positive" if positive values of surge rate represent
> >>>>>>>>>>>>>>>> the platform moving forward as viewed by an observer on
> >>>>>>>>>>>>>>>> top of the platform facing forward. The value of the
> >>>>>>>>>>>>>>>> direction attribute is "negative" if positive values of
> >>>>>>>>>>>>>>>> surge rate represent the platform moving backward. The
> >>>>>>>>>>>>>>>> directionality of surge rate values is unspecified if
> >>>>>>>>>>>>>>>> no direction attribute is present. platform_sway_rate:
> >>>>>>>>>>>>>>>> Platform is a structure or vehicle that serves as a
> >>>>>>>>>>>>>>>> base for mounting sensors. Platforms include, but are
> >>>>>>>>>>>>>>>> not limited to, satellites, aeroplanes, ships, buoys,
> >>>>>>>>>>>>>>>> ground stations, and masts. Sway rate is the rate of
> >>>>>>>>>>>>>>>> displacement along an axis (the Y axis) that is
> >>>>>>>>>>>>>>>> perpendicular to both the local vertical axis (the Z
> >>>>>>>>>>>>>>>> axis) and the nominal forward motion direction of the
> >>>>>>>>>>>>>>>> platform. Sway rate might not include changes in the
> >>>>>>>>>>>>>>>> ?at rest? position of the platform, which may change
> >>>>>>>>>>>>>>>> over time. The direction for positive values of sway
> >>>>>>>>>>>>>>>> rate is specified by an attribute named direction. The
> >>>>>>>>>>>>>>>> value of the direction attribute is "positive" if
> >>>>>>>>>>>>>>>> positive values of sway rate represent the platform
> >>>>>>>>>>>>>>>> moving left as viewed by an observer on top of the
> >>>>>>>>>>>>>>>> platform facing forward. The value of the direction
> >>>>>>>>>>>>>>>> attribute is "negative" if positive values of sway rate
> >>>>>>>>>>>>>>>> represent the platform moving right. The directionality
> >>>>>>>>>>>>>>>> of sway rate values is unspecified if no direction
> >>>>>>>>>>>>>>>> attribute is present. platform_heave_rate: Platform is
> >>>>>>>>>>>>>>>> a structure or vehicle that serves as a base for
> >>>>>>>>>>>>>>>> mounting sensors. Platforms include, but are not
> >>>>>>>>>>>>>>>> limited to, satellites, aeroplanes, ships, buoys,
> >>>>>>>>>>>>>>>> ground stations, and masts. Heave rate is the rate of
> >>>>>>>>>>>>>>>> displacement along the local vertical axis (the Z
> >>>>>>>>>>>>>>>> axis). Heave rate might not include changes in the ?at
> >>>>>>>>>>>>>>>> rest? position of the platform, which may change over
> >>>>>>>>>>>>>>>> time. The direction for positive values of heave rate
> >>>>>>>>>>>>>>>> is specified by an attribute named direction. The value
> >>>>>>>>>>>>>>>> of the direction attribute is "positive" if positive
> >>>>>>>>>>>>>>>> values of heave rate represent the platform moving up
> >>>>>>>>>>>>>>>> as viewed by an observer on top of the platform facing
> >>>>>>>>>>>>>>>> forward. The value of the direction attribute is
> >>>>>>>>>>>>>>>> "negative" if positive values of heave rate represent
> >>>>>>>>>>>>>>>> the platform moving down. The directionality of heave
> >>>>>>>>>>>>>>>> rate values is unspecified if no direction attribute is
> >>>>>>>>>>>>>>>> present. Grace and peace, Jim
> >>>>>>>>>>>>>>>>
> >>>>>
> >>>>
> >
> >
>
> --
> Kenneth E. Kehoe
> ?? Research Associate - University of Oklahoma
> ?? Cooperative Institute for Mesoscale Meteorological Studies
> ?? ARM Climate Research Facility - Data Quality Office
> ?? e-mail: kkehoe at ou.edu | Office: 303-497-4754 | Cell: 405-826-0299
>
> _______________________________________________
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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/>
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