questions about the process in 1944

[+frex3wv]

First off - hi to one and all - I haven't disappeared - just been busy and "lurking" on here only.

I hope everyone is well in their neck of the woods!

 

I will be going out to find a benchmark etc on New Years day with a newbie. My question is twofold (and is non-specific to the mark i will be hunting):

 

Back when they set marks in 1944 on rugged hilltops - did the survey party commonly build and than leave the towers that they used - or haul them in and take them to the next spot. The reason I ask - I am never sure whether to look for remnants (which I think we would all agree would be neat to find) of the towers - or just not bother (and I am not sure i would know if I found it - as the remnants simply could look like a stack of rocks etc correct?). Also, was it common for the party to stay on sight for a week or so - or would that simply have to do with weather conditions etc (as I read about in an article about a mark placed in my area). I sure wish there were some sort of "journal" entries I could read about the folks who worked in my area and what life was like in a survey party at that time!

 

Second question is - were marks set - and than others set based on the light being shot from one to another and so on and so on down the line? I have looked at the map and there really doesn't seem to be a pattern - but maybe I am missing it. (and by the way - if you map out the airway beacons by county - you can REALLY see a pattern - which is pretty cool!)

 

Thanks in advance y'all!

[Bill93]

As I understand it, horizontal control triangulation parties set stations where there was good visibility of other stations (hilltops, etc), at about the desired distance of a few miles from those other stations for economy, and where their locations made good "strong" geometric figures. Then they raised the instruments and signals to the necessary height to see all the other stations around. In many cases that was with a portable "Bilby" tower and in earlier surveys or where they did not need so tall a tower, they built wooden towers, in some cases perhaps improvised. The triangulation networks were usually a string of quadrilaterals or central-point polygons, with the chain of figures several miles wide and covering a route of 10's to a few hundred miles before linking to the mesh of other routes.

 

Vertical control benchmarks were set along routes that were easily traveled and had clear lines of sight forward and backward but without regard to sideways visibility. That usually meant along a railroad or highway where such existed. These routes were set up perhaps 10's of miles apart in a loose mesh. A leveling party traveled along this route shooting from one backsight to the next foresight in 300 foot or shorter sights. They applied every correction factor that could be identified and took extreme pains to get best possible accuracy. They had to do each route forward and backward with good agreement or else repeat until the problem was found.

 

I have seen some diagrams of the coverage in prior posts, but don't have a ready link.

[tdx]

http://www.history.noaa.gov/tools/surveytech.html has a wealth of information about how they placed bench marks in various time periods.

 

http://www.photolib.noaa.gov/cgs/index.html is the photo archive for CGS, so you can "see" how they did it, lots of great pics there.

[NGS Surveyor]

I'll add some links to supplement the good information that "Bill93" provided:

 

http://celebrating200years.noaa.gov/founda...al/welcome.html (An article on the national survey network created by the U.S. Coast & Geodetic Survey (now National Geodetic Survey). See the sidebars covering surveying methods and a movie showing the expansion of the national network.)

 

http://celebrating200years.noaa.gov/survey...rs/welcome.html (Article on all types of survey towers used by the USC&GS and NGS.)

 

http://celebrating200years.noaa.gov/magazi...by/welcome.html (This is a paper on Bilby Towers.)

 

I wrote the three articles above and there are more historical articles written by others on the 200th anniversary web site (go to "Home" from the above links).

 

GeorgeL

Former chief of NGS Bilby Tower Triangulation Party G-19

[+frex3wv]

George (and Bill and TDX):

 

Thanks for the replies - I find all the history VERY interesting. When I find marks - I like to try and envision the folks that did it - what it would have been like in the area at the time etc etc.

 

As it regards the towers - am I right that in my area - the rural hills of WV - that timber towers would have been more the norm than the bilby towers/ I simply can't see people erecting the bilby in some of the places I have been - for a couple of reasons: A) they were long "pack ins" B ) the terrain is such (rock ledges etc etc) that it would seem to have been tough to erect one safely. With that being said - i am stil curious - should I look for and expect to find any remnamts of the survey party that set the marks?

 

It was also interesting about where they stayed - but do y'all have knowledge of what life at an encampment was like - for instance - did these guys work hard all day - than put a few back while sitting around a fire at night - turn in - and do it all over again the next day?

 

Lastly - when I look at the old photos - it sais party of "Jim Smith" (made the name up). How can we tell by the datasheets who set the marks and if there are pics of their particular "party" etc anywhere to be found (same question for marks set by the usgs - which some of us have recently tried our hand at).

 

I know i have more reading to do - but it seems like pointed questions may help folks understand what i am try to learn. It is gearing me up for a few hunts over the next few days!

 

Thanks again.

Edited December 28, 2007 by frex3wv

[ArtMan]

frex3wv,

 

Check out the NGS history pages at http://geodesy.noaa.gov/INFO/NGShistory.shtml

 

In particular, browse through the C&GS Album of Historical Images. There's some really cool stuff there, such as this one (to select one random image):

 

 

-ArtMan-

[+Harry Dolphin]

Curious. And interesting. I sort of thought they put them on the top of all the tall local hills/mountains. I've never thought of plotting them for polygons. We have several from the 1800's, but most are from the 1930's. (Well, not counting the ones up and down the rivers set in mud in clay tile pipes in 1913, that have never been seen again...) I always figured that they were placed randomly, on the tallest peaks.

I've never found atower, but I did find the footings for one.

[+Klemmer]

Here's the much smaller tower we found left at TZ1994. I think it's the only towers remains I have found.

[Papa-Bear-NYC]

Here's station "Forest Park" in queens from 1903. 3 of the 4 foundation blocks that the tower legs were set in are still visible as well as the station which uses the old style CGS tablet.

 

KU3315

 

 

Another view showing the station and one of the foundation blocks.

[Team Fawlty]

I have always been curious as to the procedure to set BMs. For instance, you have a long run of them alongside some road roughly a mile apart. Did a local concrete contractor go through first and set all the monuments and the surveyors came back later or did the surveyors themselves set them and come back later to measure. Also, many times you see where a local firm replaced a destroyed RM. Did they get reimbursed somehow? Inquiring minds.

 

Brendan

[Team Fawlty]

Dupe

Edited December 29, 2007 by Team Fawlty

[NGS Surveyor]

Well, I just read through the posts since my last post and identified about 6 questions which I will attempt to answer.

 

1. Did USC&GS use timber towers, even after Bilby’s were introduced? (For stations with long packs, and rough, rocky terrain.)

A. Wooden towers were used for a few years after Bilby’s were invented in 1927 (wooden towers were still in use in the mid-1930s.). See: http://www.flickr.com/photos/12262796@N06/2158945675/

for a photo of a mountain top tower built in AZ in 1934.

 

Bilby Towers came into being because wood was getting very expensive and the reusable steel Bilby towers saved a lot of money. Regarding erecting towers on mountain tops, the reconnaissance team that selected the sites for the survey marks attempted to select locations that not only resulted in well shaped triangles (good geometry for strong mathematical solutions), but also attempted to select locations that could be driven to with a 4-wheel drive vehicle. A better choice would be a mountain top with no trees so that a tower was not necessary. Back about 1980, I helped pack a ~25-ft steel tower into a survey station in CT, a location that could not be driven to. So, after a long answer, wooden towers may have been built on wooded mountain tops even after 1927.

 

2. Should one be able to find any remnants of the survey party?

A. Ideally, the only difference to the terrain after the survey crew left should be the marks themselves. The survey crews took pride in “leaving the area as they found it” and creating neat, good looking survey marks. That said, in remote areas sometimes dimensional lumber was left behind to help future surveyors find the location and sometimes the 4-foot stands were left behind. Occasionally a Bilby tower would be left standing if it was anticipated to be needed for the next season’s work. When this was done, the top portion of the tower would be removed to reduce the “windage”. This was called “topping” the tower. If another project came up and the crew didn’t return, the Bilby could be left standing for years. I know of a few places where this happened. Today, the only standing Bilby tower that I know of is at Cape Canaveral in Florida. If anyone gets there please send me a photo!

 

3. Where did they stay? What was camp life like? Did they “put a few back” sitting around a fire?

A. There are many interesting photos of USC&GS camp life in the on-line NOAA Photo Library at: http://www.photolib.noaa.gov/ . I have copied a few of them to my FLICKR account (nickname GELSS), see: http://www.flickr.com/photos/12262796@N06/...in/photostream/

And scroll through the 12 camp photos.

 

From these one can see that families were often with the survey crews and that house trailers came into usage in the 1930’s (the most recent photo with the blue Ford van is of my old house trailer).

 

4. Are the tower footings in the posted photos from Bilby survey towers?

A. Most likely not. Normally, Bilby Towers did not have concrete footings, the anchors were simply buried in the ground, see drawing on FLICKR at: http://www.flickr.com/photos/12262796@N06/2152015797/ (from the Bilby Tower manual). I have heard of a few cases where Bilby’s were anchored in concrete when the plan was to leave them there for a long time. The concrete tower bases in some of the submitted photos may have been the bases for forest fire lookout towers or some other type of more permanent tower. Lookout towers and Bilby Towers were both built on the highest ground to provide good views. Remember, Bilby Towers normally only stood at a given location for a few weeks (until the survey observations were completed and checked.)

 

Photo of sand bags in place to anchor Bilby tower in CT: http://www.flickr.com/photos/12262796@N06/2158945713/ In rocky terrain where anchor holes could not be dug, sand bags were piled on the base of the tower to steady it and guy wires might be added. Guy wires were normally not used because they caused the tower to vibrate when a wind was blowing. Note, this 37 foot Bilby tower was the shortest we built in the 3 years I was on the survey party (short trees at this location). Normally we built 77 ft or 90 ft Bilbys. The given height was the instrument height (top of inner tower). The outer tower was 10 feet taller.

 

A Bilby Tower has three legs and these legs are equally spaced around the survey mark so that the mark is at the center of the triangle, see diagrams at: http://docs.lib.noaa.gov/rescue/cgs_specpu...35no1581940.pdf

Page 2. (“Bilby Steel Tower for Triangulation”, USC&GS Special Pub. No. 158.)

 

5. The small “tower” at TX1994” is actually what we call a “4-foot stand”. This was usually constructed at the base camp and transported to the survey station. Usually they were re-used at other survey stations. A 4-foot stand was used instead of a tripod because it was more rigid allowing higher quality survey observations. These are probably the only evidence one would find today at a survey station, and not very often. I have seen a few photos on Geocaching showing 4-foot stands. See two photos of erect 4-foot stands on FLICKR at: http://www.flickr.com/photos/12262796@N06/2152057769/

and http://www.flickr.com/photos/12262796@N06/2152849156/

 

6. Who set marks, how and when? Are firms reimbursed for replacing survey marks?

For leveling surveys, advance teams set the bench marks. For triangulation crews, the survey marks were set the same day the Bilby Tower was erected. For some photos, of a Bilby Tower being erected and the survey marks, see: http://celebrating200years.noaa.gov/magazi...come.html#tower

For a photo of one of our mark setting trucks see:

http://www.flickr.com/photos/12262796@N06/2159790486/

and note the concrete mixer behind the auger. After the hole was dug, the auger was swung off to the side and a trough was put in place to funnel the concrete from the mixer into the hole.

 

Today not too many marks are replaced. There is no program to reimburse firms or individuals for resetting marks. We do have written guidance for resetting vertical bench marks. Sometime they are replaced by NGS field crews, by NGS state advisors, by NGS contractors doing other work that needs the mark, or by private firms through some sort of cooperative project.

 

Hope all this helps.

GeorgeL

NGS

[+Harry Dolphin]

I have not found many remains of towers. Of course, I'm in New Jersey, and housing develpments destroy such things.

These are the remains of the footings for the tower of the 1936 reset of HAMBURGH 1882

 

 

 

And the anchor for the guy wire:

[+jwahl]

I have been to many stations in the western states where the 4-foot stand (not really a tower), was still existing in the immediate area of the station. It is sometimes still roughly in place over the point, but has usually been set aside so that the station could be occupied by conventional surveying equipment on tripods, other sight targets, and/or GPS on tripods. In western mountain and desert areas wood materials often survive a long time.

 

- jlw

[+frex3wv]

Thanks to all for the continued info. I wil continue to read and learn to get a better picture of how everything went down. When I found my first mark of the new year - HX3029 - I noticed that nearbye was a firepit built of stone that clearly hadn't been used anytime recently - could that have been done by the party - or subsequently built by locals?

 

Also (while slightly off topic) - there is tons of timbering going on all around the marks I found - do timber companies generally know about benchmarks and not to disturb them - or should they be given the heads up?

[+frex3wv]

*Bump*

 

Am still curious if anyone has an answer for my last question - directly above.

 

Thanks.

[CallawayMT]

Thanks to all for the continued info. I wil continue to read and learn to get a better picture of how everything went down. When I found my first mark of the new year - HX3029 - I noticed that nearbye was a firepit built of stone that clearly hadn't been used anytime recently - could that have been done by the party - or subsequently built by locals?

 

Also (while slightly off topic) - there is tons of timbering going on all around the marks I found - do timber companies generally know about benchmarks and not to disturb them - or should they be given the heads up?

 

frex3wv,

 

I do exterior boundaries for Plum Creek Timber Company in this area and I can tell you for a fact that the foresters would not have any need for bench marks or tri-stations; their main concern is where is our boundary and so, where are the cadastral and subdivision corners located. They are looking to get as close to their boundary as possible and get as many trees as they can within their logging plan. They would do their best to protect any survey marks if you do inform them of any within their logging boundaries and show them where they are located; you may have to explain to them what it is that you are showing them.

 

CallawayMT

[VagabondsWV]

Thanks to all for the continued info. I wil continue to read and learn to get a better picture of how everything went down. When I found my first mark of the new year - HX3029 - I noticed that nearbye was a firepit built of stone that clearly hadn't been used anytime recently - could that have been done by the party - or subsequently built by locals?

 

Also (while slightly off topic) - there is tons of timbering going on all around the marks I found - do timber companies generally know about benchmarks and not to disturb them - or should they be given the heads up?

 

frex3wv,

 

I do exterior boundaries for Plum Creek Timber Company in this area and I can tell you for a fact that the foresters would not have any need for bench marks or tri-stations; their main concern is where is our boundary and so, where are the cadastral and subdivision corners located. They are looking to get as close to their boundary as possible and get as many trees as they can within their logging plan. They would do their best to protect any survey marks if you do inform them of any within their logging boundaries and show them where they are located; you may have to explain to them what it is that you are showing them.

 

CallawayMT

 

I agree with CallawayMT, the timber folks are lookng for the property line(most of the time anyways, they do tend to stray a bit at times, tho). I don't think there is too much concern generally speaking in the course of the timber cutting phase for damage to our local marks. The most likely scenario of possible disturbance would be a log storage/staging area where there is a great deal more surface disturbance with dozers, loaders, etc. If there is a particular station in danger, most of the crews would protect it if notified I would think. Now as far as nuisance that is another thing, ie., would they shove brush & dirt, say along a logging road, up against a bank or over a boulder where a BM is placed, you bet. A nusiance to recover yes but mostly no harm done. But then again this is no worse than gas companies, railroads, and state road crews just to name a few doing their thing either. My 2 cents.

 

VagabondsWV

[Z15]

6. Who set marks, how and when? Are firms reimbursed for replacing survey marks?

 

Back in 1996 I ran into a NGS recon team setting BM's up here in da UP of Michigan. I was coming out from a local park and a guy was pulling a tape measure across the road in front me near the location of a BM I new about at a RR x-ing. It was just 2 guys (1 young and one older) with a white Chevy 4x4 utility truck. The only tipoff they were NGS was a stash of orange witness post in the overhead rack and gov't issue plates. The 4 man level party was working in the area on another line to a CORS. They had a beat up Chevy 4x4 suburban and the rod men were moving with small motorcycles.

 

I reset many BM's over the years while I was with the MDOT (retired in '02) and helped the advisor move a tri station or two. The NGS advisor gave us supply disks and the orange witness posts but we incurred all the other costs, which were charged to highway projects as necessary engineering costs. Often private firms would contact the advisor and he would ask us to go do it, even though he had a truck and equipment, he complained he was not allowed to do that anymore. We did not mind doing it for him as he was a good guy and always gave us all the support we needed.

Edited January 9, 2008 by Z15