I am having a complete brain fart today. I am retracing a set of corrected surveys performed in 1910 in Brewster County and I am seeing ties to elevation benchmarks place throughout the area. I am not seeing any of the marks in the online NGS database. I assume this is an early level loop run through the area. I know we have discussed these before and where to find them but I just cannot put the correct terms in the search box to come up with posts that discuss these early leveling programs.
Found it!
Kept searching and finally found a good post on the topic.
[msg=181698] https://surveyorconnect.com/index.php?mode=thread&id=181698 [/msg]
Probably USGS (US Geological Survey) Bench Marks that never found their way into the NGS Database (most didn't in my neck of the woods UNLESS the USC&GS/NGS leveled through them at a later date).
You should be able to get data from the USGS though (although I don't have any contact data for Texas).
Loyal
I'd forgotten about that post...now where did I leave my coffee cup???
On a related note, the USGS Bulletins referenced in that link (and many others covering other states), are a fantastic resource. Unfortunately, the USGS stopped publishing these in the late 30s, so more recent Bench Marks require contacting the USGS directly (see Dave Doyle's post).
Loyal
> I am having a complete brain fart today. I am retracing a set of corrected surveys performed in 1910 in Brewster County and I am seeing ties to elevation benchmarks place throughout the area. I am not seeing any of the marks in the online NGS database. I assume this is an early level loop run through the area. I know we have discussed these before and where to find them but I just cannot put the correct terms in the search box to come up with posts that discuss these early leveling programs.
You're retracing a stadia survey made by R.S. Dod, I assume. The reason Captain Dod connected to the USGS Benchmarks that he did was two-fold.
1. They were typically iron posts with bronze caps that fell along roads and were readily recognizable.
2. They were plotted on the 15-minute quadrangle maps of the area which meant that they served as a graphical aid by which Dod could position his survey on the quad sheet. His files include old quad sheets, in fact, where he has plotted the surveys on the sheet, presumably from the ties to the posted benchmarks. I'd think that rectifying the old quad on a modern map and digitizing lats and longs of the benchmarks from the rectified quad sheet would get you close enough to find them.
Here's a detail of the Agua Fria, 1917 quadrangle, for example. Note how each of the benchmarks is identified by its posted elevation (which Dod would have mentioned).
USGS Publications (historic)
For those of you who may interested in finding "older" USGS publications related to Leveling, Traverse, Triangulation, etc. in YOUR area...
Publications of the Geological Survey 1879-1961
http://pubs.er.usgs.gov/publication/70043703
This 'book' is a great resource for finding out what has been published by the USGS in YOUR area.
Loyal
BTW, note that where Dod gives bearings to objects described as "mont." or "monument" on some peak or hill, he was probably referring to the cairn that the USGS left at a triangulation station on that peak or hill, some of which are in the NGS database.
I was not familiar with that USGS Historical Topographic Map Explorer. I've bookmapped that for future reference.
I found the area of my interest on page 108 of Spirit Leveling in Texas, 1896 to 1915. Looks like the runs were based on an aluminum monument in the southeast cornerstone of the Brewster County Courthouse in Marfa. It was recovered in 1996 by US Power Squadron but a Geocacher could not locate it in 2010. Of course, the elevations aren't important to me as much as witness to Dod's work on certain section corners. I think the systems of surveys I am working through, there are 4 of interest including one at the mouth of the Santa Elena Canyon and the one you reference at Agua Fria. The Agua Fria Quad is available in the Twichell records at the GLO website.
Btw, I found a whole mess of survey reports in the "Miscellaneous File Under Stair" now known as Brewster County Rolled Sketch 125. Still need more time with the correspondence files, tho.
>The Agua Fria Quad is available in the Twichell records at the GLO website.
Note that you can download an excellent scan of the quadrangle map from that USGS site I linked above, as well as modern quad sheets upon which it could be rectified.
There is also a very good collection of USGS quad sheets available on line here:
http://www.lib.utexas.edu/maps/topo/texas/
Yes, the Perry-Castaneda collection is very handy.
BQ0122'IN MARFA, SET VERTICALLY IN THE SOUTH FACE OF THE SOUTHEAST CORNER
BQ0122'STONE OF THE COUNTY COURTHOUSE, 0.6 METER (2.0 FT) WEST OF THE
BQ0122'SOUTHEAST CORNER OF THE BUILDING.
BQ0122'THE MARK IS 0.3 M ABOVE THE GROUND.
and
http://www.geocaching.com/mark/details.aspx?PID=BQ0122
They say it appears to be covered by stucco. You could still measure from the corner and/or use a treasure-hunter metal detector to determine its location within a tenth or so.
> BQ0122'IN MARFA, SET VERTICALLY IN THE SOUTH FACE OF THE SOUTHEAST CORNER
> BQ0122'STONE OF THE COUNTY COURTHOUSE, 0.6 METER (2.0 FT) WEST OF THE
> BQ0122'SOUTHEAST CORNER OF THE BUILDING.
> BQ0122'THE MARK IS 0.3 M ABOVE THE GROUND.
>
> and
>> http://www.geocaching.com/mark/details.aspx?PID=BQ0122
>
> They say it appears to be covered by stucco. You could still measure from the corner and/or use a treasure-hunter metal detector to determine its location within a tenth or so.
While Andy didn't explicitly say as much, I'm pretty sure that he doesn't really care about the vertical datum marked by the benchmarks. What he is dealing with is a survey out in the middle of nowhere that was tied to a couple of posted benchmarks in place along roads out in the middle of nowhere. If he can determine the HORIZONTAL POSITIONS of those posts, he has a means of at least computing some preliminary search positions for the survey corners in the block of surveys situated between the benchmarks.
My experience with the surveyor he is following is that unless you get really lucky, you need to begin at some identifiable corner and follow the survey from corner to corner along the intervening miles until you get to the area of interest. The survey he is retracing was performed by stadia methods, so my guess is that it may well contain errors of more than 50 ft. per mile. That may mean that the search positions have radii of at least a couple of hundred feet unless he has some other clues to use to narrow things down.
Well, he mentioned that it had been found and then not found, as if he did have some interest in it.
USGS Publications (historic)
Loyal, thanks for the link. Now can you find the person at USGS that knows
anything about getting the OLD "Triangulation Diagrams"?
JOHN NOLTON
Tombstone, AZ.
> Well, he mentioned that it had been found and then not found, as if he did have some interest in it.
If he's really worried about that benchmark at the post office, I'm afraid something has slipped off the tracks on that project.
What interested me to learn how R.S. Dod had used the posted benchmarks in South Brewster County was how they remain so relevant for their horizontal positions rather than their vertical. I ran across this about twenty years ago on a project I worked on in Brewster County in the vicinity of Elephant Mountain. The benchmark remained in place in the middle of nowhere along the side of the former road between Marathon and the cinnabar mine in Terlingua, one of the few absolutely identiable marks that Mr. Dod had tied to. His work was otherwise riddled with many uncertainties, so it was pleasant to be able to identify something solid and definite.
Actually, I explicitly said I didn't need elevations. Just casually interested in its existence.
>Of course, the elevations aren't important to me as much as witness to Dod's work on certain section corners.
But good to know it might still be there if needed.
USGS Publications (historic)
Ya got me John...
The last time that I contacted USGS in Denver, THE GUY had retired, and there were only two guys who could help, and they only did it "part time." I don't remember who I talked to there, but he was GREAT, and got me the data that I needed. That was a year or two ago, and HE might be retired now too!
Loyal
USGS Publications (historic)
Nolton, what area do you need and what is the year of the network? I can get them for you.
USGS Publications (historic)
Jerry Penry, thanks for the offer. Over the years (from 1961) I have some. I only wish I had got the whole United States. It would be best if I gave you a list of what I do have and we can go from there.
JOHN NOLTON
Tombstone, AZ.
PS I have tried NGS to get a contact number at USGS because NGS turned over the job
of making them to USGS sometime after 1980(?); no luck--heck the people I talked with at NGS don't even know what a Triangulation Diagram is.
USGS Publications (historic)
The Geodetic Control Diagrams (GCDs) and the associated insert diagrams were always produced by USC&GS/NGS. They were compiled by the Cartographic Section of the NGS Information Center using the USGS 1:250,000 scale (1x2 degree) maps and NOS coastal charts until the end of fiscal year 1983, when the effort was stopped. The cartographers were all transferred to the NOS Aeronautical Charting Division and the GCDs were distributed as requested by the NGS Information Center until supplies were depleted. Several years ago all of the remaining stock was trashed and a couple of copies of each diagram were archived. While the base for the GCDs were the USGS maps that agency was never involved in their publication or distribution.