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base9geodesy
base9geodesy
@base9geodesy
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Joined: January 19, 2013 8:51 am
Last seen: May 28, 2026 2:28 pm
Topics: 18 / Replies: 236
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RE: GPS third order accuracy

Third-Order - Do you mean horizontal/geometric or vertical or both? The order of accuracy terms (e.g. First-, Second- and Third-Order) are defined na...

11 years ago
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RE: How to use LaPlace without understanding what it is!

Careful with your convergence angle. The convention is that you add algebraically (add if positive, subtract if negative)- the same as the LaPlace co...

11 years ago
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RE: NGS Mark Recovery: Alternate Website

I prefer using the recovery submission in DSWorld -- DSWorld. It also allows me to submit updated positions for bench marks with only scaled position...

11 years ago
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RE: Ellipsoid to NAVD88?

You will love the new vertical datum NGS plans to role out in 2022 - bench marks will be a thing of the past, they will not define the datum - the ver...

11 years ago
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RE: Ellipsoid to NAVD88?

So what you're saying is you're using the slope of the geoid height differences not "the geoid." This makes sense. While the absolute accuracy of th...

11 years ago
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RE: Ellipsoid to NAVD88?

Could you please clarify what you mean by "applying the geoid to the elevations instead of the ellipsoid." I don't understand what you're trying to s...

11 years ago
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RE: Ellipsoid to NAVD88?

You should also be aware of how accurate NGS thinks the geoid model in your area is - GEOID12A accuracy maps

11 years ago
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RE: NSPS Elections 2015

Sorry, I meant Done - that's what happens when you type in Base 9!!

11 years ago
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RE: GPS Ellipsoidal Height Geoid

First, it is important to make sure of what you are trying to accomplish. When you say MSL to you really intend it to be Mean Sea Level. MSL is a sp...

11 years ago
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Replies: 1
Views: 1007
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RE: NAD 83(2011)

Adjusting the geometric reference frame (i.e. NAD 83 (2011)) is a MASSIVE undertaking. Given the resources required to perform such a task I would su...

11 years ago
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RE: Convert L,L,H to N,E,El

While the GRS80 and WGS 84 ellipsoids are virtually the same the ITRF is a coordinate system not an ellipsoid. Since the DoD keeps redefining WGS 84 ...

11 years ago
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RE: Convert L,L,H to N,E,El

WGS 84 and NAD83 differ by approximately 1m horizontally across the lower 48. They are NOT mm difference.

11 years ago
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RE: Convert L,L,H to N,E,El

Be very careful. SPCs are defined legislatively in NAD 83 only.

11 years ago
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RE: HO scale survey screw

USC&GS Special Publication 158 "Bibly Steel Tower for Triangulation" -- authored by Mr. Bilby himself.

11 years ago
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RE: NGS datasheets for reported destroyed marks.

If you know the PID go to "Datasheets by PID" page. In the menu below the box where you enter the PID select the tab that says "Include Destroyed Mar...

11 years ago
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RE: Reciprocal Leveling

For updates to the NGS River Crossing investigations you should contact either John Ellingson ([email protected]) NGS Wisconsin state geodetic a...

11 years ago
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RE: Vertical Reference Frames

The definition or realization of the new vertical datum to replace NAVD 88 (and the other island datums) in 2022 will not include any bench marks - it...

12 years ago
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RE: Vertical Reference Frames

In and of itself, sea level change (up or down) should not have a significant impact on a nation's vertical datum. Every vertical datum I've ever see...

12 years ago
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