Jerry - I solved for the triangle and get a slightly different NAD 83(1995) position from yours:Latitude = 41-41-00.19 NLongitude = 102-52-53.55 WNebr...

Gaham MarionThis is indeed very sad. I remember, or at least I'm told I remember that night very well. You would have been hard pressed to find a gr...

And So You Did, But It Is A Non-ProblemActually most of the eastern U.S. (east of western Nevada) is moving generally SW at approximately 1.5 cm per y...

I suspect that the FEMA contractors used just the existing leveled NAVD 88 control in the area to produce the maps. As noted previously the various g...

First note that GEOID12A is not a datum, it is a model that allows you to estimate NAVD 88 orthometric heights from NAD 83 (2011) ellipsoid heights. ...

Since the OPUS difference is almost exactly 1 m (0.975) and it's higher, I going with someone recorded or entered a bad antenna height as the most lik...

The 1992 date for the NAVD 88 height on the datasheet is the just the date when the adjustment was published, not when the leveling was performed. Fo...

Two questions. How much did the marks not check by? Where are these stations located?Much of southern Mississippi is an active subsidence zone. You...

You may find some very useful material in the NGS webinars --

Oops Sorry -- [email protected]

While it was not the norm for USC&GS to not stamp anything triangulation disks back in the 20s, it was also not especially unusual. David is righ...

Ken Sorrels, VA LS 1780What a good guy. He was always working on something interesting. I will certainly miss him.

To simply perform a conversion from UTM to geographic position there is no real need to compute the combine factor. In the case you expressed you can...