[LandXML] Re: LandXML vertical angle clarification
- From: "Yates, Kenneth W." <KWYATES@xxxxxxxxxxxxxx>
- To: <John.Halleck@xxxxxxxx>, "Kevin Murphy" <KMURPHY@xxxxxxxxxxxxxx>
- Date: Thu, 17 Jul 2003 14:25:54 -0400
as a surveyor,
we maintain a "face" tag on each horizontal angular observation reading
from the theodolite.
The FACE attribute MUST be carried thru the data reduction of multiple
horizontal angle pointings.
The vertical angle (Zenith Angle) is easier to follow: 1 thru 180
implies "direct scope" and
180 thru 360 is "inverted scope". =20
I have never seen Modern electronic survey equipment output a negative
Zenith Angle.
A survey "Total Station" instrument is oriented either in "direct" or
"inverted" FACE for any of the three types of measurements it makes:
HzAngle, Zangle, SlopeDistance.
By the way, 270 degees Zenith is also at station-level (horizon)
We are currently attempting to create a XML that supports
raw-survey-readings for our survey notes... from this rawsurveyXML we
can output LandXML without having to change the LandXML spec.
below is a snippet of the Zenith portion of our observation record:
please note that we glom all the zeniths together, regardless of the
"face"... then reduce the average to the direct face reading mode:
<vert-angle zenith=3D"86.635625">
<zenith-average zenith=3D"86.635625" stddev=3D"0.00261">
<zenith-sample zenith=3D"86.637778"/>
<zenith-sample zenith=3D"273.365556"/>
<zenith-sample zenith=3D"86.637778"/>
<zenith-sample zenith=3D"273.3675"/>
</zenith-average>
</vert-angle>
-----Original Message-----
From: John Halleck [mailto:John.Halleck@xxxxxxxx]=20
Sent: Thursday, July 17, 2003 2:06 PM
To: Kevin Murphy
Cc: landxml@xxxxxxxxxxxxx; john.halleck@xxxxxxxx;
nathan.crews@xxxxxxxxxxxx
Subject: [LandXML] Re: LandXML vertical angle clarification
On Thu, 17 Jul 2003, Kevin Murphy wrote:
> Date: Thu, 17 Jul 2003 13:49:57 -0400
> From: Kevin Murphy <KMURPHY@xxxxxxxxxxxxxx>
> To: landxml@xxxxxxxxxxxxx, john.halleck@xxxxxxxx
> Cc: nathan.crews@xxxxxxxxxxxx
> Subject: [LandXML] Re: LandXML vertical angle clarification
>=20
> John,
> With zero directly overhead and 90 degrees on the horizon, it should
> not matter
> what side of the instrument you stand on. The horizon is always at
90
> degrees.
I realise this...=20
But that is not what the description says.
The description that Mr. Crews offers is in
terms of "clockwise". Which means, as a software developer,
I'm free to have the horizon -90 degrees.
Rewording it to say that it=20
"Represents zenith angles with the 0 origin as straight
up and measured such that the horizon is positive in the
specified Angular Units"
Would be closer to what I would expect in the official
definition.
> If you are referring to the angle if the scope of the instrument is
> inverted ( reversed),
> then the Zenith angle would be 360 - Z.
>=20
> hope this helped...
> -Kevin
>=20
>=20
> >>> John Halleck <John.Halleck@xxxxxxxx> 07/17/03 01:19PM >>>
> Nathan Crews says:
> "Represents zenith angles with the 0 origin as straight=20
> up and measured in a clockwise direction in the specified Angular=20
> units."
>=20
>=20
> If I change which side of the instrument I'm standing at,
> which way is clockwise for a vertical angle changes.
>=20
> I therefore find this confusing.
>=20
>=20
>=20
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