12 September 2007

Blank Elevation Marker from Camping Trip

From the camping trip, you may remember this photograph, which shows an elevation marker, which I was informed should be called a "benchmark." For some reason the Geological Survey neglected to stamp the elevation on this benchmark.

A few days after the trip, I sent this message to the United States Geological Survey via the contact page.


While on a camping trip with some friends in the Zaleski State Forest in Ohio, I saw an elevation marker. I have seen several of these in other places, but this one did not have the elevation stamped on it. Could you tell me what the elevation is for this marker?

I posted a photograph of the maker here: http://bp0.blogger.com/_QHTs4OUpJ2M/RtnSxU5kbJI/AAAAAAAAA5U/H11w7z-SO5c/s400/Hike_3.JPG

Thank you,

Later that day, I received a response.
--------------- Original Message ---------------
Subject: Re: Blank Elevation Marker
Date: Tue, 04 Sep 2007 11:38:20 -0400

September 4, 2007

Thank you for your request.

The USGS office in Rolla, MO. holds all the records for benchmarks in the eastern half of the U.S. I will forward your inquiry to that office.

If you have any other questions, please feel free to contact us again.

Soon, I received a reply from the office in Rolla, MO.

09/04/2007 03:31 PM

Subject: Re: Fw: Blank Elevation Marker

Luke C.:

Thank you for your inquiry in regards to a bench mark in the Zaleski State Forest in Ohio. Additional information is needed such as: Latitude/Longitude, Township, Range, Section#, Topo map name if known, Stamping or BM# shown on topo map. If you would furnish me with additional information I will look up the information for you.

This response was surprising because I thought the benchmark would contain enough information to allow the staff at USGS to uniquely identify it. Also, I did not know how to find much of the information requested. While I was pondering how to respond, another very helpful message arrived.

On Tue, 04 Sep 2007 16:43:43 -0500 John C Fouke wrote:


If you do not have an easy way to find the lat-long, T-R-S, topo map name, etc., then the fastest method might be for you to visit www.topozone.com, and find the location of the benchmark there (you can view our maps on topozone) so that Mary can find the benchmark description in our paper files.

After a relatively easy search on topozone, I had the information they needed.

"Luke A. Corwin"
09/05/2007 08:18 AM
RE: Fw: Blank Elevation Marker


Thank you for pointing me to Topo Zone; I was able to find the benchmark easily. It is designated "BM 723" on this map:


What does "17 CBT" mean. It was stamped on the maker before "1959," as you can see in the photograph I linked in my original message?

Thank you,

With this, the staff at USGS were able to tell me exactly how high we (or more precisely the soles of our shoes) were above sea level we we stood next to this benchmark.

"BM 723" Ohio is in the 15' quadrangle = 41OH Line 2, Page 4.

The original mark is Third-Order Leveling, National Geodetic Vertical Control of 1929:
Zaleski, 6.0 mi NE. of; 1.4 mi NE. of Hope; in Sec. 15, T. 11 N., R. 16 W.; 35 ft N. and 30 ft E. of, and 2 ft higher than centerline of State Highway 278 at concrete bridge over Sandy Run; in top of guardrail; standard tablet stamped "17 CBT 1959 723" Elevation 722.872 feet


Zaleski, 6.0 mi NE. of, 1.4 mi NE. of Hope, Sec. 15, T. 11 N., R. 16 W., 178 ft NE. of bridge #278-8.59, 22 ft W. of centerline of concrete base of tie-down for guard rail; standard tablet stamped "17 CBT 1959 RESET1982" RESET ELEVATION 722.333 feet (221.082 meters)

What does "17 CBT 1959 723" mean?
The USGS fieldman stamping method is:
17 is the line number (Example next number 18, 19 and so on)
CBT is the fieldmans initials (C. B. Thomas)
1959 is the year the line was ran
723 is the elevation rounded off (If below 5 would be 722 if above 5 would be 723) For this elevation 722.872 it is rounded off the 723.
RESET shows that the mark has been reset since original bench mark was established
1982 shows the year the RESET was done

So there's your information on USGS bench mark training. USGS does not have a website address. NGS has a website: http://www.ngs.noaa.gov You can go to the Products and Publications and it explains bench marks. I have copied how to get to the information on the website below.

If you need additional information please let me know.

Mary Fone

NGS Website: http://www.ngs.noaa.gov
Left side column click on Products & Services
Scroll down to Publications
Click on Publications Available On Line
Scroll down to Operations, Field Procedures
Click on Geodetic Bench Marks

NGS Website: http://www.ngs.noaa.gov
Below Surveyor click on datasheets
Below Retrieval Links click on gray DATASHEETS
Select Retrieval Methods
USGS Quad Name (Without the State)
Click on Submit
Below ST select the 2 letter state then click on Submit
It will display the marks
Click on Select All (Will display in blue)
Then click on Get Datasheets


Celia said...
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