MathTeacher, post: 362261, member: 7674 wrote: Back in 2007, I was teaching math to high school and community college students and teaching myself what I could about surveying and geodesy. Communication towers were a convenient means for verifying some of the principles that I thought I learned. The FCC maintains location data on all registered towers and they are easy to find on county GIS systems, so very good location data is easy to come by.
FWIW, the NGS database includes a large number of intersection stations: water towers, radio masts, stacks, church steeples, etc. These points were located by intersection during triangulation projects.
Use the NGS Data Explorer tool to find them graphically. As an example of an area with an abundance of such points, see Quonset State Airport in Rhode Island. To get near the area search Quonset, RI then look for the airport. Click on the open triangles to get the point name and to access the link to its datasheet.
I did a triangulation network on this airport and could have avoided measuring any distances to position the new fixed control. Of course, I did measure everything as a check.
Using these intersection stations is problematic as many of them have been changed over the years (new steeples, moved lights, moved tanks, etc). I did not realize why the folks at the Walla Walla Penitentiary were so hesitant to tell me whether they had changed their water tank. Then it dawned on me.
HTH,
DMM
Began triangulating points back in the 1970s because of high water, yards full of dogs and grumpy people and other dangerous critters and posted boundaries.
Before EDM when we chained between control points we would turn angles from every hub we could see them from for checks and mean the calculated point.
Nate The Surveyor, post: 362363, member: 291 wrote: Well, rfc above, I certainly applaud your efforts. What kind of distances are you talking about?
I've got 3 locus L1 units gathering dust here. With a download ir wire. And some software.
You'd have to have an older 32 bit xp or Windows 3x machine to process it.
I tried to sell them on ebay, but tiger whatever, (inst dealer in Florida) tried to play hardball, to buy them. I have them still. I think one has battery corrosion issues. But the other 2 are good.
Wow Nate; Bless you! That would certainly change my game, big time. But really, I'm not sure I'm ready yet to tackle GPS (although from what I read about L1's, operating them is pretty simple).
My test area is less than 1/2 mile long and 1000' wide; mostly moderate to steep woods (but with one open field I'm using to nail down the solar and polaris stuff). As for old 32 bit machines...I have half a dozen! Just picked up two at the local recycling center this weekend. I clean them, refurbish them and either give them to charity or bring them back to the recycling center and put them on the table for "used but working" stuff. I love restoring old electronics in general. So that part wouldn't be a problem.
The real problem is two fold:
1. I don't want to get diverted (yet) from my current work with the total station. My network so far stretches about half way up the 1/2 mile; I expect to do the other half this summer. There's still much to learn (and not as much time as I'd like). It'd probably be cool to use static to combine the data with all I've got in Star*net, and to use it as a check for my assortment of observations.
2.I'm extremely budget constrained though. the Commander in Chief (and occasional Prism Girl) is a partner here and while she has been alerted that my next purchase will be a full seat of Star*net (used or otherwise), she's pretty savvy to everything on my eBay watch list:angel:. So spending any money right now on GPS would probably be frowned upon (understatement).
Perhaps at the right time though, I can take the L1's for a spin; refurbish them (new batteries, knobs, whatever electronic repairs might be needed); use them to learn the basics, then return them in fine enough shape for you to sell on eBay for a reasonable price. Let's stay in touch on the subject.:-)
Several intrested bidders. But the guy in Florida was high bidder, and second bidder. Multiple ebay names.
If I put them back on, I'll cancel any of his bids. He goes back a ways. It's not the first time he's tried stuff.... It wastes your time and effort, and they
Rfc, where do you hail from?
Are you a student?
Is this just an intelectual exercise?
Tell us your story.
N
Nate The Surveyor, post: 362401, member: 291 wrote: Rfc, where do you hail from?
Are you a student?
Is this just an intelectual exercise?
Tell us your story.
N
Cliff notes version:
Vermont, Yes, and Yes.
I think I did many moons ago. Looking for it now, lol. If I can't find it, I'll write something.
GeeOddMike, post: 362392, member: 677 wrote: FWIW, the NGS database includes a large number of intersection stations: water towers, radio masts, stacks, church steeples, etc. These points were located by intersection during triangulation projects.
DMM
Thanks, Mike. Many smokestacks and steeples have survived here in Piedmont NC. Exploring the NGS map was an interesting exercise.
That's a good tool. Were you part of its development?
GeeOddMike, post: 362392, member: 677 wrote: FWIW, the NGS database includes a large number of intersection stations: water towers, radio masts, stacks, church steeples, etc. These points were located by intersection during triangulation projects.
Use the NGS Data Explorer tool to find them graphically. As an example of an area with an abundance of such points, see Quonset State Airport in Rhode Island. To get near the area search Quonset, RI then look for the airport. Click on the open triangles to get the point name and to access the link to its datasheet.
I did a triangulation network on this airport and could have avoided measuring any distances to position the new fixed control. Of course, I did measure everything as a check.
Using these intersection stations is problematic as many of them have been changed over the years (new steeples, moved lights, moved tanks, etc). I did not realize why the folks at the Walla Walla Penitentiary were so hesitant to tell me whether they had changed their water tank. Then it dawned on me.
HTH,
DMM
I have used a few of the triangulation points before. One of them being the old Carnation stack at the facility in Gustine, California. It isn't owned by Carnation any more, but it is still there. And it checked out just right for me.
rfc, post: 362328, member: 8882 wrote: The best example I've seen was that survey of the Himalayans someone linked to here.
If your interested read the book 'The Great Trigonometric Survey of India'. Read this as a teen and it got me interested in the subject. Long story there. If you want to see some good illustrations of the maps produced, just google up that title. It was one of the most amazing feats of it's time. Mt. Everest was named after George Everest who was in charge of the survey for much of it's duration. It's a great read if your interested in survey history.
I use triangulation on occasion to locate difficult or dangerous to access improvements. Just another tool in the kit.
I bet a lot of people would freak out setting a corner by doulbe chaining it in and probably don't even carry a plumb bob any more even in their truck.
Not involved at all.
Nate The Surveyor, post: 362401, member: 291 wrote: Rfc, where do you hail from?
Are you a student?
Is this just an intelectual exercise?
Tell us your story.
N
Nate:
Well, I went back to July 4, 2014, the day of my first post:
https://surveyorconnect.com/threads/dts-302-or-dts-203-newbie-needs-advice.267895/
To see exactly how I presented myself to the good folks here initially, and found (not surprisingly), that three posts in, YOU, Sir, blessed me with this comment:
" If you were doing that in my 'hood, I'd ask you to bring your notes to my office, and we'd crunch them together. And, then I'd recommend whatever additional ties, loop closures, etc. Then go again. My fees would be that you have to buy me lunch, for a while, at some local deli, while we discuss the project. The sheer labor involved in doing this thing right, (your labor) would probably turn this into a labor of love pretty fast. You would become either my next field hand, (if you did a good job), or you would discover that surveying is not for you. Either way, unless you tried to tell me how to survey, we would become friends!
I'd give you a worksheet, and search locations. Before it was done, you'd either be in the club, out of the club.
We'd have doubled angles, and ft meters in your book.
Modern Surveying.
It's work.
N"
Of the many naysayers that responded to my early (somewhat clueless) posts, piling on about "surveying without a license", YOU saw, and understood what I was trying to do, and have provided a great deal of inspiration since. I remember thinking of getting on a plane to Arkansas and taking you up on your lunch offer (if not vicariously being your field hand, lol).
Since those days, when I was looking for some tiny "attaboy" for achieving a 5000:1 closure using a prehistoric Topcon AG2 and a steel tape, I've progressed in less than two years to achieving over 50,000:1 in a 20 node control network. And, I'm not even past page 300 in Ghilani and Wolf yet (except for the multitudes of "sneak peeks" ahead to look up such stuff as triangulation. (I learned by the way that what I'm doing currently with my network involves more trilateration than triangulation).
But I've got no deadlines; I've developed an enormous respect for the Art and those that engage in it; And I'm really, really enjoying the process, and really appreciate the input and support from folks like you and many others here.:stakeout:
In my area there is a tower on a ridge about 10 miles away. So, I set several points using GPS and OPUS solutions, and observed astro azimuths. Azimuths spanned from NE to south. A total of 9 points and the tower. By this exercise I was trying to see how well the azimuths would fit. Distances were 10-70 thousand feet. StarNet Demo takes a max of 10 pts. and it worked out pretty well. 95% confidence region 12x6 cm. Residuals to the azimuths were 0" to 8" seconds. I had many, many azimuths, stars and solar. I created a comprehensive Excel sheet for the azimuth reduction, which alone was well worth it. Had to relearn a lot.
I highly recommend the exercise.
I also setup a 10 point parking lot network to investigate subtense distances. Lengths up to 168 meters, and an over determined triangulation net. GPS OPUS for checks. 1:20,000, but I'm working on tighter.
And that is triangulation writ small.
Every once in a while I will locate some inaccessible point horizontally by triangulation. I've measured the heights of several towers by traversing away from the tower and turning angles to the top.
One of the more interesting ones was a water tower that was near a subdivision. The nearest homeowner's insurance company hired me to see if the house was within the possible fall radius of the water tower. It was about 8 feet outside the radius. The height of the tower measured within 0.1' of what the water association manager told me.
Larry Scott, post: 362548, member: 8766 wrote: I created a comprehensive Excel sheet for the azimuth reduction, which alone was well worth it.
Is this spreadsheet something you'd be willing to share?
Here are a couple of fun triangulation apps at Google PlayÛ?
https://play.google.com/store/apps/details?id=kr.sira.measure&hl=en
https://play.google.com/store/apps/details?id=in.co.boilerplate.triangulation&hl=en
Might be useful for ÛÏestimationsÛ. B-)
rfc, post: 362557, member: 8882 wrote: Is this spreadsheet something you'd be willing to share?
I would be happy to share, as long as I get some feedback.
It takes all (all that I know of) data entries directly from field notes. Web links for DUT, Laplace, work sheet for stop watch offset calcs, or UTC time entry, 2016 solar (left right center) and Polaris ephemeris built in, up to 8 multiple FS. Individual accept/reject for easy editing. (I have an altered version for mils.) Any star RA/Dec entry (external ephemeris req'd, and I use the UK Hydrographic Service's ephemeris for land surveyors). I am short on instructions, although it should be easy enough to figure out if you have astro experience. Culmination, transit times, Astro, geodetic and UTM azimuth output. I've been revising it for over a year, and I haven't found a bug in quite sometime. I can copy notes from a field excercise as example. Ive tested it against Elgin & Knowles, and NREL(Mica), one-up same results (0.5" or so).
Actually, I can reduce 4 sets of 8 D/R as fast as I can key in the data, 10 minutes or so. (It's become my azimuth software of choice, but I'm biased.) I've shot at least 40-50 sun, and a dozen star shots.
But, I'm used to it, so I can't tell how intuitive it really is. I think so, if you're not new to the subject. And if you're new, there'll be questions. I'll have to make a readme doc, there's a lot to it - at first. I've been meaning to write instruction.
That's where shooting azimuths to published towers are useful.
Larry Scott, post: 362596, member: 8766 wrote: I would be happy to share, as long as I get some feedback.
It takes all (all that I know of) data entries directly from field notes. Web links for DUT, Laplace, work sheet for stop watch offset calcs, or UTC time entry, 2016 solar (left right center) and Polaris ephemeris built in, up to 8 multiple FS. Individual accept/reject for easy editing. (I have an altered version for mils.) Any star RA/Dec entry (external ephemeris req'd, and I use the UK Hydrographic Service's ephemeris for land surveyors). I am short on instructions, although it should be easy enough to figure out if you have astro experience. Culmination, transit times, Astro, geodetic and UTM azimuth output. I've been revising it for over a year, and I haven't found a bug in quite sometime. I can copy notes from a field excercise as example. Ive tested it against Elgin & Knowles, and NREL(Mica), one-up same results (0.5" or so).
Actually, I can reduce 4 sets of 8 D/R as fast as I can key in the data, 10 minutes or so. (It's become my azimuth software of choice, but I'm biased.) I've shot at least 40-50 sun, and a dozen star shots.
But, I'm used to it, so I can't tell how intuitive it really is. I think so, if you're not new to the subject. And if you're new, there'll be questions. I'll have to make a readme doc, there's a lot to it - at first. I've been meaning to write instruction.
That's where shooting azimuths to published towers are useful.
Wow! I've been banging my head trying to sync MICA, the Carlson Solar routine, and a DOS program Lee Green had, without much success. I'll start a conversation with my email address (unless you'd post it), and promise to give you feedback.:-)
Sometimes we must kick back and accept that taking our next breath is the single most important thing in the world. Everything else is just the icing on the cake.
There are days when I want to chuck it all and be satisfied with living in a gunny sack in a hollowed out log somewhere dry and warm.
If you're really interested, and are familiar with Astro, I'd gladly share. In the interest of not embarrassing myself (if the spreadsheet isn't ripe for the general group) I'll let rfc be the first. Then we'll see if it's suitable. Like I said, I'm too familiar, and no one has looked at it. So ... I'll gin up a readme. It's visually very busy. But only input cells are unlocked, and, well you'll see, couple of days. I don't know who takes sun shots these days. So, if there's interest, rock on.
And Astro is as much art as math. As my sheet got better, so did my observation techniques.
Are you a stop watch, micrometer user?
