Hi Jim, all,
I'm a bit confused by the "clockwise" and "anticlockwise". You
mention the orientation of the observer but not the
location/orientation of the clock. My assumptions (not sure why) for
the clock: for roll, the observer (who is facing forward) would be
facing the clock; for pitch, the observer would look right to see the
clock; and for yaw, the observer would look down to see the clock.
That works for your definitions of pitch and yaw, but is backwards
for roll.
Does "clockwise" add, in some way, another degree of freedom to the
definition? Does that degree of freedom need to be nailed down in the
definitions? Or other terms used instead? I don't have any good
suggestions other than "positive" and "negative".
Cheers,
Ethan
On Wed, Aug 29, 2018 at 9:03 AM Jim Biard <jbi...@cicsnc.org
<mailto:jbi...@cicsnc.org>> 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
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