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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: Reciprocity and PR licensing

If you want to get licensed in PR contact Ms. Ruth Trujilo ([email protected]) Presidente Instituto de Agrimensores.?ÿ I am sure she will be very ...

8 years ago
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RE: State requires survey accuracy statement...

A professional surveyor should never use a measurement tool or procedure for which they are unable to provide a reliable statistical assement.

8 years ago
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Replies: 12
Views: 1277
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RE: EDM history

The U.S. Coast & Geodetic Survey, now the National Geodetic Survey began using EDMs in the mid-1950s.?ÿ The first were the Geodimeter Model 2 from...

8 years ago
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RE: Old USC&G benchmark data needed!

I should have added this in my previous post for completeness.?ÿ The distances of arcs was fairly easily computed back then by using USC&GS Specia...

8 years ago
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RE: Old USC&G benchmark data needed!

Back in the day it was common practice for USC&GS chart cartographers to show arc seconds of latitude and longitude in meters.?ÿ To convert 1385 a...

8 years ago
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RE: Surveyors Week March 18-24, 2018 GPS on BM

For your observations to be a part of this program they must be submitted to OPUS Shared Solutions

8 years ago
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RE: Using Vertically Mounted Bench Marks

It is important to note that the xGEOID models (currently xGEOID17 and later this year xGEOID18) do not provide an estimate of NAVD 88.?ÿ The model co...

8 years ago
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RE: Mean Sea Level

As previously noted NGVD29 was previously called the Sea Level Datum of 1929.?ÿ It was never the Mean Sea Level Datum of 1929.?ÿ Actually the original...

9 years ago
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RE: Bench Mark Stability

At the 95% confidence level no state (or territory) has a 1-2 cm geoid uncertainty with GEOID12B. In general even in states where the model performs ...

9 years ago
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RE: Bench Mark Stability

I have it from a long time friend and colleague at NGS that there will likely be one more hybrid geoid (GEOID18?) to be released. The approximate tim...

9 years ago
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RE: NGS Datasheets Archive

John Hamilton and Bill93 are both correct about USGS vertical control in the NGS database. USGS declined to automate their data and submit it for inc...

9 years ago
Topic
9 years ago
Replies: 5
Views: 851
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RE: PROBLEMS WITH POSITION OF GPS POINTS.

The ITRF which is a product of the International Earth Rotation and Reference System Service does not have its own ellipsoid. Coordinate values are o...

9 years ago
Topic
9 years ago
Replies: 1
Views: 417
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RE: On the fly GPS "calibration" against benchmark

A soap-box of mine - unless you are working in Earth-Centered Earth-Fixed coordinates a bench mark will not have a "Z" value. Orthometric heights are...

9 years ago
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RE: Vertical Datumns, OPUS, FEMA

It would be most excellent if Mr. Best could determine the VIVD09 height for one or more of the three actual survey marks I posted previously that FE...

9 years ago
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RE: Vertical Datumns, OPUS, FEMA

Mr. Best ,Go the NGS datasheet retrieval page by county - . Under "Pick a State" scroll down and select US Virgin Islands, then select "Get County Li...

9 years ago
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RE: Vertical Datumns, OPUS, FEMA

Larry Best - Regrettably FEMA and a number of other federal agencies often show heights in the island areas of the U.S. as either NGVD 29 or NAVD 88....

9 years ago
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