Long Lake revisited

Posted in Colvin points on August 19th, 2012
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Well we finally got back up to Long Lake to finish our search of two winters ago. Under the direction of Steve Sehnert and with the cooperation of a beautiful summer weekend, many points were recovered.  A full write up will follow shortly.





Lake Placid follow up

Posted in Colvin points on February 28th, 2011
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         On October 30, 2010, I was able to make a return trip back to Lake Placid to attempt to find the three points comprising V. Colvin’s “great baseline” extending from Signal Hill down to the southerly shore of Lake Placid and then across the lake to Hawk Island. The original measurements of the land segment of this baseline is detailed below under “measuring bars” and represents one of the more precise measurements ever made in the Adirondacks.

With the invaluable assistance of Bob and Dan Marvin who provided GPS services and a boat, we were able to recover the north base mark on Hawk Island.

Colvin’s signal over the mark is as shown here:

Unfortunately, the station on the south shore of the lake (if still in) rests under a newly laid, imported stone patio that I don’t think the owners would have taken kindly to if we dismantled it. We then proceeded to Signal Hill to search for the mark that was listed in 1946 as being destroyed by road construction. After numerous 3-4 feet deep test holes were dug in the gravel road nothing was found.

Special thanks goes out to Northern and Bob and Dan Marvin for their assistance in completing this recovery.

Jim Vianna





How accurate was Colvin’s work

Posted in Colvin points on November 10th, 2009
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I am often asked “how accurate were Colvin’s measurements”.

         Well, based on the extremely small sampling that I have personally re-measured, I would say it varies from better than what is typically obtained today to god awful. The better work appears to be that in which Colvin personally performed the observations and the worst appears to be that which was performed in his absence.

The following link, will take you to a web page entitled: “Kinematics and Dynamics of Strain Accumulation in the Adirondacks” USGS 1434-94-G-2473, Final Report by John Beavan, Lamont-Doherty Earth Observatory of Columbia University, Palisades, NY 10964

This 1995 report details the use of Colvin station marks in helping to determine the movement of the Adirondack Mountain range. A resulting un-intended conclusion of their work is found in the report  as follows: 

“Conclusion: The 1800′s triangulation surveys of the Adirondacks resulted in horizontal station coordinates precise to about 0.5 m (when selecting the best data available to us). The 1940′s survey resulted in precisions of 0.1-0.2 m. The 1995 GPS data gives precisions estimated at 0.01-0.02 m. The accuracies of the earlier surveys, while commendable for their time, are insufficient to detect deformation associated with the uplift of the Adirondacks.”

 Jim Vianna

 





Colvin Reports Now Available

Posted in Colvin points on August 5th, 2009
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The N.Y.S. Library is in the process of scanning and electronically publishing all of Colvin’s reports to the N.Y.S. Legislators (and the maps found in those reports). A large portion of this work has now been completed and is available for downloading. The scans are in .pdf format and may take a considerable period of time to appear on your computer. I suggest the use of their FAQ page if you encounter problems. You will not be able to bookmark each report as they use a constantly changing URL. The best way to gain access to the downloads is by clicking below, then selecting the “search digital collections” bar located near the top of the page and then type in “Verplanck Colvin” in the search window

Colvin Reports





Measuring Bars ???????

Posted in Colvin points on July 7th, 2009
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I first came across these pictures while visiting the Adirondack Research Center of the Association for the Protection of the Adirondacks about two years ago. Having never seen anything like this in the surveying world previously, to say it caught my interest is an understatement. Well, after keeping my ears open, I finally obtained the last Colvin report published for the years 1898-1899 which was edited by fellow crew member Norman J. VanValkenburg and published in 1989. Much to my surprise, therein was found a detailed report on the use of these measuring bars as written by Professor E. A. Fuertes, Director and Dean of the College of Civil Engineering of Cornell University. This report details the Professor’s work at Lake Placid in August of 1897.
                 While I admit that the following report is an exception rather than the norm for the expected accuracy of Colvin’s work, I find it extremely interesting and worthy of an easy future recovery.

  These two pictures show the crew measuring down the slope of land towards the shore of Lake Placid

 (Note: the use of two instruments in this process)

V4

                                     V5

 

 

 

 

 

 

 

 

 

 

 

 

Here is the actual report as told in Prof. Fuertes own words and as extracted from “REPORT OF THE SUPERINTENDENT OF THE STATE LAND SURVEY OF THE STATE OF NEW YORK FOR THE YEAR 1898″ edited by Norman J. Van Valkenburgh , The Adirondack Research Center of the Association for the Protection of the Adirondacks, 1989, first edition.

(Click on the individual page to open it in a larger window for ease of viewing)

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scan0002

  scan0003

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 scan0005

 

 Items worthy of note are: The Professor being upset with the monument being 1 mm out of position, 20 days to go 1,144 feet and a difference in the two runs of 0.002± of a foot.