> It would be a lot of fun to run your own traverse through his points and compare your coordinates with his when you're done. Try not to peak as you go. You may surprise yourself or maybe realize how tough the surveyor's job really is. 🙂
Indeed it would be interesting to see how close I got to his work! Last time I did this I found 7.5ft bust:-P Ended up hiring new surveyor;-)
It is tough job but to much fun! Every single time I set out to do my "recreational survey" I feel like a kid in the candy shop. When I found an old monument it felt like I found the most precious item on the planet!
You have two excellent references and you may find that many of us here have different editions of the same.
I have Charles Ghilani's Elementary Surveying tenth edition and Barry Kavanagh's Surveying Principles and Applications second edition. If you have different editions the organization may vary slightly. However, the chapter titles and content within the chapters will be similar.
The differences between unadjusted and adjusted values **should** be less than what you would notice when you go out and BS with your shiny new coordinates
Yoginatha! I think you have been infected by the Survey Bug! I remember those feelings. In fact, I still feel like that sometimes. I don't think you'll find a cure. The only treatment is to go forth and survey....
> You have two excellent references and you may find that many of us here have different editions of the same.
>
> I have Charles Ghilani's Elementary Surveying tenth edition and Barry Kavanagh's Surveying Principles and Applications second edition. If you have different editions the organization may vary slightly. However, the chapter titles and content within the chapters will be similar.
Aloha, Dallas:
I have Ghilani's 13th edition and Kavanagh's 9th edition. Glad to know I found two good books!!
> The differences between unadjusted and adjusted values **should** be less than what you would notice when you go out and BS with your shiny new coordinates
Thanks Stacy. I got it--finally! Aloha
:hi5:
How Many Buildings On this 70 Acre Site?
Your buildings should be as stable as any control point. Building corners with coordinates are excellent for free stationing backsights. Favorite corners should get permanent targets/reflectors.
Also any radio antennas, windmills, metal high tension towers on or within sigth distance should have coordinates added.
It should not take many traverse control points to blanket 70 acres and it is doubtful that free stationing will be needed much.
Paul in PA
How Many Buildings On this 70 Acre Site?
> Your buildings should be as stable as any control point. Building corners with coordinates are excellent for free stationing backsights. Favorite corners should get permanent targets/reflectors.
>
> Also any radio antennas, windmills, metal high tension towers on or within sigth distance should have coordinates added.
>
> It should not take many traverse control points to blanket 70 acres and it is doubtful that free stationing will be needed much.
>
> Paul in PA
Aloha, Paul:
Good thoughts! However, our building are clustered in one or two places on the parcels. When I am closer to the buildings I will definitely use them per your suggestion. See attached image. There are swamps, hills and heavy vegetation that need to be traversed through. I think that is the reason my PLS setup his RTK GPS where he can to avoid traversing through tough areas.
Unfortunately, there are no antennas or other high towers.
FWIW: Our local county code doesn't allow any building to be higher than a coconut palm tree:-) Only exception to this is the Marriott Hotel. This is the only structure taller than coconut palm besides 100+ years old sugarcane mill towers--mostly gone already. The Marriott was the reason for the restriction, to make sure it didn't happen again. That is one reason we don't see any tall structures that could be used as target.
I scanned a lot of the answers. For me, I had to learn more by "doing" than by reading. (but of course both, but actually doing things made me understand better what I read about it.)
I agree with Bill93 in regards to not worrying about angles close to 180º. The angle simply gets you a direction, and the distance meter gets you a distance. I no longer buy in to the old "strength of figure" philosophy. But that is a tough argument.
I also agree with whoever mentioned calculating your coordinates, closures and adjustments by hand at first. That helped me contemplate about closures and better understand the different adjustment types and the advantages and how they worked, etc.
Good luck, and have fun.
Tom
> I scanned a lot of the answers. For me, I had to learn more by "doing" than by reading. (but of course both, but actually doing things made me understand better what I read about it.)
>
> I agree with Bill93 in regards to not worrying about angles close to 180º. The angle simply gets you a direction, and the distance meter gets you a distance. I no longer buy in to the old "strength of figure" philosophy. But that is a tough argument.
>
> I also agree with whoever mentioned calculating your coordinates, closures and adjustments by hand at first. That helped me contemplate about closures and better understand the different adjustment types and the advantages and how they worked, etc.
>
> Good luck, and have fun.
> Tom
Aloha, Tom:
Thanks! I am thinking about doing simple traverse first and do the calculation by hand. I am also very much hands on person. I began to read the books but I felt I'd get more practical approaches here at Surveyor Connect. If there are more thoughts you or anyone want to share please let it flow out freely!
Yoginatha,
I don't know whether your reference books or any previous threads have mentioned using three tripods and three optical-plumb tribrachs. It's a simple way to reduce field error in a traverse, and generally makes it fairly easy to achieve 1:50,000. We used to do it back in the 1970s when EDMs were less accurate.
> Yoginatha,
>
> I don't know whether your reference books or any previous threads have mentioned using three tripods and three optical-plumb tribrachs. It's a simple way to reduce field error in a traverse, and generally makes it fairly easy to achieve 1:50,000. We used to do it back in the 1970s when EDMs were less accurate.
Aloha, John:
It was mentioned before for my prism offset check. John Hamilton suggested that I keep the tripods and tribrachs in place to avoid centering errors. This is what you meant right?
Thank you so much!
Agree w/John and John. We always called it leapfrogging. I liked keeping the same tribrachs in place and clipping in and clipping out. But you may not have tribrachs that will accommodate that.
> Agree w/John and John. We always called it leapfrogging. I liked keeping the same tribrachs in place and clipping in and clipping out. But you may not have tribrachs that will accommodate that.
Aloha, Tom:
Thanks for the confirmation. I purchased additional tripod and tribrach from ebay. At some point I may need to get one more tripod.
Have to wait until my budget recovers...:-D
That's right, you'll need three tripods to make that method work. You'll also need three tribrachs with optical plumbs, and on many total stations the plumb is in the gun rather than in the tribrach. You can unsnap the gun from the tribrach but you can't set up the tribrach by itself, as you need to do in leapfrogging.
Happily you are not under any time pressure. In the meantime you can pick out the locations for your traverse points, which can take awhile if you haven't done it before. Some tall stakes, 6 feet or so, are often helpful in making sure the points are intervisible. Best wishes.
> That's right, you'll need three tripods to make that method work. You'll also need three tribrachs with optical plumbs, and on many total stations the plumb is in the gun rather than in the tribrach. You can unsnap the gun from the tribrach but you can't set up the tribrach by itself, as you need to do in leapfrogging.
>
> Happily you are not under any time pressure. In the meantime you can pick out the locations for your traverse points, which can take awhile if you haven't done it before. Some tall stakes, 6 feet or so, are often helpful in making sure the points are intervisible. Best wishes.
Aloha, John: Thanks for the clarification.
Yes, I am not under any pressure. These parcels are my only survey project 🙂
So far I spent couple days figuring out the traverse route. I did exactly what you said. We have bunch of 6' tall fiber glass rods. I used them to temporally set the inter-visible stakes. It hard to keep distance equal. Some places I can go for about 800' then there are one or two only 200' or so. I assume this is normal.
Thanks again for your input!
Yes, there is nothing unusual about traverse legs of varying lengths. It's better to avoid very short legs, such as under 100 feet, due to the effect of sighting error. As you may know, sighting error has more effect on the accuracy of the angle on shorter legs. Of course turning the angle multiple times reduces that error.
On shorter legs we used to unscrew the small sighting rod from the reflectors and sight the mounting screw underneath, which stuck up about 1/2" from the bracket and was visible through the scope at 200 feet or so. That made it easier to center the vertical crosshair and thus reduced the sighting error. It might or might not work with your reflectors, depending on how they are set up.
It occurs to me that the leapfrog method would work with three tripods, two tribrachs with optical plumbs, and the tribrach from the instrument without a plumb. When it's time to move the plumbless tribrach ahead, you could set it up with the instrument on it, then unsnap the instrument, snap on a reflector, and move the instrument back to the middle point to turn the angle. It would take a little more time but would be just as accurate.
All the best,
