The concept of non-recording states still boggles my mind.

The article says it was knocked down and rebuilt. If there were no accurate reference ties then the position is officially destroyed, not just "pres...

I noticed that, too, but you should probably identify yourself as the spelling police to make it clear to all readers what the point was.

Can you explain a bit more about what all the pointers on the displays mean? They appear fascinating with so many indications. I hope the ship has so...

I have some 'prime' merchandise I could trade you.

I see you aren't pricing them rationally.

So I misinterpreted your words. I thought spikes were the control points and couldn't see why they would be moving so much, but you meant spikes on t...

Do the spikes actually move that much or is most of the problem keeping a tripod stable on the asphalt? There have been numerous suggestions for the ...

I should have said the temperature correction would be negligible. With almost no pressure, the basic speed of light would apply rather than the nomi...

But the total air pressure on Mars is so small, about 0.6% of Earth's mean sea level pressure, that the correction would be negligible for most purpos...

The problem is that it isn't just a good mark that got destroyed. The codes say NGS doesn't have good data for this mark. I did note that going throu...

The problem is that it isn't just a good mark that got destroyed. The codes say NGS doesn't have good data for this mark. I did note that going throu...

I was excited to see this article. In some ways it helps answer questions I was looking into in prior threads. Dave's information quoted by Jerry li...

Somewhere around here I have a picture of a badly bent single-engine plane that I had ridden in a year or so earlier. A control cable broke on takeof...

So the principle difference between the old survey and yours was 0.4 ft difference between the datum they used and NGVD29? One has to ponder the relat...

If you can talk them out of iron above ground, my preference would be iron rods well below the surface with gray PVC capped pipe slipped over the rod ...