Super Tall Geodesy

Posted by: StLSurveyor

Another great post high-jacked.

This is the same BS that drove and still drives members away.?ÿ

Such a waste of energy.

Thank you for all the time assembling the OP.?ÿ

Oh, cƒ??mon. ?ÿWho doesnƒ??t enjoy a good thread hijack?

They call me sidetrack boy.

squirrel!

Hi-jack, vs. High Jack.?ÿ

Wait for it.....

Posted by: StLSurveyor

Another great post high-jacked.

This is the same BS that drove and still drives members away.?ÿ

Such a waste of energy.

Thank you for all the time assembling the OP.?ÿ

In this particular case, no high- (or hi-) jack occurred.?ÿ One poster asserted that the original poster had made an error in his computations.?ÿ Elevations must be reported in International Feet not U.S. Survey Feet.?ÿ Others correctly challenged that assertion.

Now as for the squirrel video and correctness of hyphenated words......

P.S.?ÿ Thanks Scott.?ÿ I always enjoy your posts.

As you were, carry on...

Great post!!!

And as for the other thing when someone can show me they can measure the difference in 5000' of elevation to .003' or whatever it calculates to with normal surveying equipment and procedures then I might start to think about US ft vs. International ft for elevations.

The state coordinate system is mandated as US feet here, I'm using it for elevations also,

#surveyporn

So, I finally found what I was looking for; an NGS document regarding Datasheet data, 3/01/2017, see below.

https://www.ngs.noaa.gov/DATASHEET/dsdata.pdf

On page 8 I found this footnote;

"1 Heights in meters are converted to U.S. Survey Feet by using the conversion factor H(USSF) = H(m) x (39.37/12.00). Height in feet is rounded to 1 less decimal place than the corresponding height in meters."

As best as I recall, this was in International Feet in the past.

Paul in PA

My question is what does the NGS have to do with a VEB Freiberger 500 meter tape. They made the tape to 500 meters I doubt they worried about feet when they made it.

Scott, GREAT post!

BTW, you have some really cool toys to play with too.

Loyal

?ÿ

"So this is an example of an International ft state where NGS still gives US feet, as noted in the quote above."

?ÿ

Ditto for Arizona.

Nice project and thanks for all the details. I hope to have time for a closer examination. I was curious about your source for the deflection of vertical values you show for ƒ??CRRNJƒ?. They differ from the output of DEFLEC12A.?ÿ

In your message you refer to a statement in Stemƒ??s SPCS manual regarding the reduction of angles and azimuth to the ellipsoid. He basically advises readers to refer to a geodesy text for the details. You indicate that you hope NGS will ƒ??address this in 2020.ƒ?

While NGS clearly states that there will be a deflection model for the new datum (DEFLEC2022), I doubt it will include the details you desire. Perhaps I am wrong but the audience for this topic may be considered too limited.

In any event, if you are interested in the corrections for the reduction of horizontal distances to the ellipsoid, I recommend the text book ƒ??Geodesy: Introduction to Geodetic Datum and Geodetic Systemsƒ? by Zhiping Lu, et al. It is a 2014 book published by Springer.?ÿ

The text covers the corrections for the deflection of the vertical, skew normals and from normal section to geodesic. I found this section of his text (pages 213-221) reasonably clear.?ÿ

It is available as an ebook, hardcover and softcover at 99/160/139 USD respectively. I have not checked Amazon or other bookseller sites. Springer has made the book available as standalone chapters at 30 USD. See: www.springer.com/us/book/9783642412448#reviews The chapter covering this issue is number 5: ƒ??Reference Ellipsoid and the Geodetic Coordinate Systemƒ? pages 165-263.

I purchased it for personal use when the text became available. I neither know the author/s nor have any financial interest in its success. It is not light reading but can be skimmed for topics of interest and more closely read for detailed information.?ÿ

In closing, I will also mention that NOAA TM NOS NGS 10 does have a breakdown of how to transform DISTANCES see pages 30-34 electronic numbering/ 24-28 page numbers of print version.

?ÿ

Hope this contributes,

DMM

Awesome post Scott.?ÿ Thanks for taking the time to show us how this was done.?ÿ It's not something that I would ever run into myself.