USGS Publications (historic)For those of you who may interested in finding "older" USGS publications related to Leveling, Traverse, Triangulation, etc...

I'd forgotten about that post...now where did I leave my coffee cup???On a related note, the USGS Bulletins referenced in that link (and many others c...

Probably USGS (US Geological Survey) Bench Marks that never found their way into the NGS Database (most didn't in my neck of the woods UNLESS the USC&...

Tis a poor craftsman that blames his tools.Loyal

I have the same question as Kent...

Thanks Gene...

@ 3½" diameter, it can be only one thing...A Geoid Adjustment Point (GAP).By putting a LARGE Crescent Wench on the top, you can adjust the local Geoid...

GEOID12a in Utah TTTJim,I don't have any HARD numbers handy, it's been a couple of years since I did one of those [type] projects. Off the top of my h...

GEOID12a in Utah TTTThis is why I adjust GPS and Leveling data independently of each other.Your mileage (and geoid undulations) may vary...

Do Y'All Still Post Nifty North Arrows Here?I thought that Santa Clause had a beard!B-)

Great news Gene!Even though I don't work in Colorado, I'm tempted to buy the DRIVE just to have all that data in my hot little fist!Can you get starte...

Just look at a globe...The meridians (lines of constant Longitude) converge at the Poles.0.01" of Longitude is much different @ 45° Latitude, than it ...

That's "close enough" for a BALLPARK number.It works "okay" for Latitude (anywhere), but you need to multiply it by the cosine of the Latitude, in ord...

HTDP & phantom vertical movementLee,The “0.004 m” that you are (probably) seeing in (I assume) a NAD83(2011) Epoch XXXX.xxxx to [say] NAD83(2011) ...

A [very] few times, some more logical than others.Elevation Equations are more common in my experience.eg. BM-12 Station 45+12.5, 65 ft. Right, Elevat...

The above sheet is dated about a month before I started surveying (9/27/1968).Filled my share of those in back in the late 60s & early 70s (don't ...