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Unfortunate Destruction

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BDT,

 

I don't believe the standards at the NGS have changed, but the value of your reporting has improved. It would appear Deb is valuing your reports with a higher regard.

 

- Mitch -

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I found one of these stem - no disks on Monday. This is one neither the NGS nor the Voldesquad could find. How would you log BL1563 with NGS?

 

 

BDT,

 

  And explained to her that it was useles for control survey purposes.

 

CallawayMT

 

Callaway, would that first example you gave have been useless if the post had not been bumped, just the disk was missing?

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Will wrote:

 

That standard is (was!): finding the stem of a missing disk with a location defined by scaled horizontal coordinates does not constitute sufficient reliable evidence to justify logging the station as "FOUND".

 

Question: Can a stem (missing disk) with scaled horizontal corrdinates could be logged as "found" if all the references checked out as published?

 

-Paul-

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Callaway, would that first example you gave have been useless if the post had not been bumped, just the disk was missing?

TerraVador,

 

As I explained earlier, I would not have used it without the brass cap intact. The purpose for it's use in my survey was for vertical control, and I am not going to risk using a damaged bench. I simply moved on to the next bench in the line. If I had no other vertical control in the area, which I did, I may have shot it and used it as a check.

 

If for some reason, I needed a bench mark in that area to run levels; and I only needed an elevation to within a foot I may use it. But I would prefer to run through another bench to check and see if it is correct, and also to absolutely verify that it was the correct bench mark. In surveying, one always prefers to have a check or verification on any work that is done, if at all possible.

 

CallawayMT

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Paul PFF wrote:

 

Question: Can a stem (missing disk) with scaled horizontal corrdinates could be logged as "found" if all the references checked out as published?

 

Paul - That is the central question of this discussion. I have always thought "no". Everyone else (including Deb) says "yes", provided the correspondence between the location of the stem and the described location in the datasheet (with measurements from confidently determinable references, etc.) is sufficiently good as to lead a [prudent benchmark hunter] to conclude with some degree of confidence that the stem observed is, in fact, a stem and not some other thing and is, in fact, the stem of the station sought.

 

I guess that an apparent stem for a station described as being mounted in a large rock outcropping north of the highway (with no further descriptive elements) would not be prudently findable under this (self-imposed, non-binding, completely voluntary, admittedly arbitrary and not-to-be-used-to-reduce-fun) decision rule.

 

Whereas, the apparent stem of a station described as being set vertically in the north face of the Bitsko County Courthouse, 2.3 feet east of the northwest corner of the building, 3.8 feet above the level of the sidewalk, and 1.1 feet above the water table would be findable (assuming the finder's observations also confirmed that the supporting courthouse is, in fact, the same edifice in which the disk was originally monumented).

 

Will

Edited by seventhings

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9/12/2005 TerraVador found BL1563    [visit log]

Retrieved coords using the X on Topozone. Coords took me to within 2 meters. Found the concrete monument with disk impression and disk stem . Disk is missing.

N30 06 33.8 W095 55 17.0

 

 

This is a good place to do another "commercial" for using decimal degrees to find benchmarks.

 

TerraVador was wise to get the coordinates for BL1563 from TopoZone, since the SCALED coordinates were inaccurate, and since the mark was conveniently shown on the topo map. Here's how he might have pinned it even closer than he did, prior to taking to the road:

 

On the TOPOZONE map, click on the "X" for the benchmark, with the UNITS set to decimal degrees (DD.DDD). In this example, I got N30.1094 W95.9215.

 

When I converted it and did some comparisons, here's how it turned out:

 

Latitude

N30 06 34 TopoZone position in DDMMSS

N30 06 33.84 TopoZone, using decimal degrees and working back to DDMMSS

N30 06 33.8 GPS reading on the scene by TerraVador

 

Longitude

W95 55 17 TopoZone position in DDMMSS

W95 55 17.40 TopoZone, using decimal degrees and working back to DDMMSS

W95 55 17.0 GPS reading on the scene by TerraVAdor

 

Now, let's say the mark was difficult to see. Perhaps we need to dig, probe, or use a metal detector. If TerraVador leaves his GPS in the decimal degree mode, he sees the digits change with very slight horizontal movement.

 

N30.1094 W95.9215 is what he is looking for as he walks toward the disk.

N30.10938 W95.92139 is what he sees when he reaches the disk.

 

Granted, it still is off a small amount. But these are scaled coordinates. When you convert ADJUSTED coordinates to decimal degrees, this system will put you practically on top of mark--if you have signals from four to six birds!

 

-Paul-

 

 

Edited for typos. [sigh]

Edited by PFF

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Ah, yes, but the X on the quad isn't always in the correct place... quads have errors, and sometimes they have gross errors.

 

For LY0834, the scaled coordinates put the mark near the X (within a handlful of pixels in the image), but unfortunately the mark was actually 960 feet away.

 

LY0834_topo.gif

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Another old thread - somewhat long, but interesting discussions on 'disk gone, stem remains' topic. Stumbled upon it while searching this forum for a place to request help to ID a disk.

 

0d2e709e-5457-4a16-8b6b-ae76dd9943c4.jpg

 

MAYBE A MT WYO BOUNDARY MP

 

Hoping that someone can CSI the lettering. Disk is not the same as MP 122 MT WY 20 miles east (GE scaled), but do believe that it is a GLO.

 

5e8dbc0d-c9c3-411b-aee2-30b0579fadd4.jpg

 

Thanks for any help. MEL

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I don't see any relationship to the old thread, so would have started a new one, myself.

 

I can convince myself I see part of GENERAL but agree is isn't the same style of disk as the other picture.

 

Have you looked at the topo map for this location to see what it shows?

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