Bruno,
Given solar_azimuth_angle parallels this definition pretty closely, would you be OK with the originally proposed name if the definition is clear?
john
On Jan 15, 2013, at 09:28, Bruno PIGUET wrote:
> Aleksandar,
>
> Thank-you for the clarification. As John said, with the diagram,
> everything becomes clear.
>
> But I fear I have no good suggestion on the way to name this
> parameter. Spontaneously, I would say something like
> "azimuth_of_sensor_seen_from_observed_point", but, clearly, this doesn't
> follow the guidelines for construction of CF Standard Names.
> At least, does this correctly reflect what you mean ?
>
> Bruno.
>
>
> Le 15/01/2013 03:20, Aleksandar Jelenak - NOAA Affiliate a ?crit :
>> Bruno, John:
>>
>> platform_azimuth_angle defines an angle where the observation point is
>> at the vertex, one side of the angle points north, the other side
>> points to the platform, and the angle is calculated clockwise from the
>> north. The observation point is defined by an instrument on the
>> platform.
>>
>> Here's one diagram explaining this angle:
>> http://science-edu.larc.nasa.gov/SCOOL/images/azimuth.gif
>>
>> platform_azimuth_angle in the diagram is labelled "Satellite Azimuth
>> from North". The observation target is labelled "Where You Are".
>>
>> I don't agree the definition is weak. It mentions that "platform"
>> means the vehicle from which *observations* are made, and clearly
>> indicates that *observation target* is at the vertex of this angle.
>> Perhaps the confusion is arising from the term "azimuth" as it is
>> widely used in ship and airplane navigation.
>>
>> I opted for "platform" in the name because I saw a standard name
>> platform_zenith_angle which can be applied to satellite zenith angles
>> and thought to complete the other two missing: satellite scan/look
>> angle and satellite azimuth angle by replacing "satellite" with
>> "platform".
>>
>> -Aleksandar
>>
>>
>> On Mon, Jan 14, 2013 at 12:29 PM, John Graybeal <jgraybeal at ucsd.edu> wrote:
>>> I agree with Bruno -- platform angle as it is defined in the request is the angle of the _platform_ with respect to a reference direction ("the horizontal angle between the line of sight from the observation point to the platform and a reference direction at the observation point, which is often due north"). The seems like platform orientation to me too.
>>>
>>> I wasn't excited about the name platform_azimuth_angle anyway, because it is ambiguous on this exact point -- is it the azimuth angle of the platform, or of the instrument on the platform? (the former, in this case). Platform_orientation seems to be the accepted name for the purpose.
>>>
>>> The definition is very weak though -- can we propose the substitution of this definition for that one?
>>>
>>> John
>>>
>>> On Jan 14, 2013, at 09:17, Bruno PIGUET wrote:
>>>
>>>> Le 14/01/2013 17:21, Aleksandar Jelenak - NOAA Affiliate a ?crit :
>>>>> Dear Bruno,
>>>>>
>>>>> On Fri, Jan 11, 2013 at 11:52 AM, Bruno PIGUET <bruno.piguet at meteo.fr> wrote:
>>>>>> I have one remark about "platform_azimuth_angle"
>>>>>>
>>>>>> I like this name and it correspond to usual navigation definition (as
>>>>>> far as I can tell from my experience with airborne and shipborne
>>>>>> measurements), but...
>>>>>>
>>>>>> There is already a standard name called "platform_orientation", whose
>>>>>> definition seems to be the same, even if less precisely-worded : The
>>>>>> platform orientation is the direction in which the "front" or
>>>>>> longitudinal axis of the platform is pointing (not necessarily the same
>>>>>> as the direction in which it is travelling, called platform_course).
>>>>>
>>>>> platform_orientation is not the same as platform_azimuth_angle. This
>>>>> azimuth angle is related to measurements made by an instrument mounted
>>>>> on a platform (satellite, ship, airplane, truck, etc.).
>>>>
>>>> Sorry for looking dumb, but I don't see the difference (except that
>>>> "platform_orientation" is not precisely defined).
>>>>
>>>> I'm currently producing CF files containing airborne measurements,
>>>> and the parameter which is usually called "heading", which is in fact
>>>> exactly defined as "platform_azimuth_angle", is qualified with
>>>> "standard_name = platform orientation".
>>>>
>>>> Bruno.
>>>> --
>>>> bruno.piguet at meteo.fr
>>>> ?quipe GMEI/TRAMM
>>>> CNRM-GAME : UMR Meteo-France/CNRS n?3589
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>>>
>>>
>>> ----------------
>>> John Graybeal <mailto:jgraybeal at ucsd.edu> phone: 858-534-2162
>>> Product Manager
>>> Ocean Observatories Initiative Cyberinfrastructure Project: http://ci.oceanobservatories.org
>>> Marine Metadata Interoperability Project: http://marinemetadata.org
>>>
>>>
>>>
>>>
>>>
>>>
>>>
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> --
> bruno.piguet at meteo.fr
> ?quipe GMEI/TRAMM
> CNRM-GAME : UMR Meteo-France/CNRS n?3589
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----------------
John Graybeal <mailto:jgraybeal at ucsd.edu> phone: 858-534-2162
Product Manager
Ocean Observatories Initiative Cyberinfrastructure Project:
http://ci.oceanobservatories.org
Marine Metadata Interoperability Project:
http://marinemetadata.org
Received on Tue Jan 15 2013 - 12:23:04 GMT
