TOPOGRAPHIC & HYDROGRAPHIC STATIONS

[NGS Surveyor]

The following quote contains some interesting history of USC&GS TOPOGRAPHIC STATIONS and HYDROGRAPHIC STATIONS (USC&GS survey disks containing those words). Note especially the last sentence which states that HYDROGRAPHIC STATION marks (disks) are no longer to be used. Previously in the MANUAL it states that many of both types of stations were located by plane-table methods beginning from third-order control Consequently many of these TOPOGRAPHIC and HYDROGRAPHIC STATIONS may be less than of third-order quality and for that reason may not be in the NGS database.

 

Quote from, “HYDROGRAPHIC MANUAL, revised 1942 ed., by Commander K. T. Adams, Coast & Geodetic Survey, pp 92-93.

 

“235. Recoverable Topographic Stations

 

Changes in topography and culture occur as the country develops, or as a particular area increases in importance, and revision surveys become necessary. Such surveys should not be undertaken until a thorough search has been made for stations established during prior surveys. The number of stations recovered may be sufficient for control of the new survey.

To provide for future use in revision surveys, the topographer shall supplement existing control by establishing additional recoverable stations so that there are control stations at 1-mile intervals along the coastline; except along rugged or swampy coastline bordering areas unfavorable to habitation or industry, where the interval may be increased to not more than 2 miles (see 2141).

These recoverable stations may be natural or artificial objects when available, or standard topographic disks set especially for this purpose, and together with other control stations provide recoverable control at the required intervals. When practicable, stations should be established where they can be easily identified, and in the most permanent places available. Conspicuous points, rock outcrops, large boulders, etc. are excellent places to set station-mark disks. Often natural or artificial objects exist which make splendid topographic stations that are recoverable without special marking. Some of the natural ones have remained intact for generations and are very likely to remain so for years to come. The establishment of a station at its most likely location will aid a later party in its recovery.

All topographic stations specially marked for future recovery shall be marked with standard bronze topographic station marks, stamped with the name and year. Reference marks are not set at topographic stations. Paragraph 29, page 7, and line 8, page 52 of Special Publication No. 144, Topographic Manual, are hereby amended by the substitution of the word "topographic" for the word ''hydrographic." Hydrographic station marks are no longer used by the Coast and Geodetic Survey and hence-forth shall be considered obsolete.”

 

For anyone interested in more information on these or other USC&GS, NOS, and NGS survey disks, see: “Bottles, Pots, and Pans: Marking the Surveys of the U.S. Coast & Geodetic Survey and NOAA” at: http://www.ngs.noaa.gov/web/about_ngs/hist...dexhUSCGS.shtml

 

GeorgeL

NGS

[Papa-Bear-NYC]

This brings to mind a disk I found a few years ago:

 

LX1097 - TIDAL 3

 

 

Notice it was originally an old "Hydrographic Station" disk which must have been manufactured in 1921 (see note in my recovery log).

 

But it was used as a tidal bench mark, so the first part of "HYDROGRAPHIC", namely "HYDRO" was over stamped with the word "LEVEL" and a bar was chiseled in the circle to make it look like a tidal bench mark.

 

I guess using an old disk that was lying around in the surveyors kit bag was standard practice.

 

It's the only one I ever found, and for that it was used for another purpose.

Edited October 27, 2010 by Papa-Bear-NYC