James Vianna, post: 382965, member: 120 wrote: I don't get the train of thought that because a position is repeatable it is accurate. You simply really don't 100% know and are assuming based on past experience. I'll use the title insurance analogy here. Title companies only go back 20 - 30 years as they rarely see problems crop up longer than that. The few times they get bit for not going back will be outweighed by the money they save doing it quickly and cheaply. RTK is no different, its a "calculated/insured risk". Whether you decide to assume this risk based on your experience or beliefs is up to you.
I am envisioning the following exchange:
JUDGE/ATTORNEY:
Please tell the court how you arrived at the distance between the two corners.
SURVEYOR:
Well I placed my new $40,000 RTK device on each corner and it told me it was okay to store the location and move on to the next point.
JUDGE?ATTORNEY
What do you mean by that
SURVEYOR
Well it averaged the location a bunch of times and the results were all with 0.10' so it must be correct
JUDGE/ATTORNEY:
So once again did YOU actually measure the distance between the corners
SURVEYOR:
Well no not in the traditional sense, I let the black box tell me the coordinates were okay to store and move on. As I'm not privy to the software code nor would be able to explain the mathematics involved, I relied on the manufacture to calculate the actual measurement, I just report what it tells me
JUDGE/ATTORNEY
So the box measured the distance, how do you know the box is correct.
SURVEYOR
Well it tells me the same answer every time. I have verified this on other jobs against conventional instruments.
JUDGE/ATTORNEY
So on those OTHER jobs the box agreed with conventional measurements, those other jobs are not why we are here, what about this job where you only used the box
SURVEYOR
well it worked great on the other jobs so it must of worked here
JUDGE?ATTORNEY
do you have an independent verification on this job that the box is correct
SURVEYOR
No, but I could go out there today and get the same answer
JUDGE?ATTORNEY
your dismissed
It seem like that exchange could be about your edm or total station, or static survey measurements in addition to an rtk measurement. It seems that the surveyor needs to be able to talk more intelligently about what s/he is doing than saying that they got the answer from the black box machine.
James Vianna, post: 382965, member: 120 wrote: I don't get the train of thought that because a position is repeatable it is accurate. You simply really don't 100% know and are assuming based on past experience. I'll use the title insurance analogy here. Title companies only go back 20 - 30 years as they rarely see problems crop up longer than that. The few times they get bit for not going back will be outweighed by the money they save doing it quickly and cheaply. RTK is no different, its a "calculated/insured risk". Whether you decide to assume this risk based on your experience or beliefs is up to you.
I am envisioning the following exchange:
JUDGE/ATTORNEY:
Please tell the court how you arrived at the distance between the two corners.
SURVEYOR:
Well I placed my new $40,000 RTK device on each corner and it told me it was okay to store the location and move on to the next point.
JUDGE?ATTORNEY
What do you mean by that
SURVEYOR
Well it averaged the location a bunch of times and the results were all with 0.10' so it must be correct
JUDGE/ATTORNEY:
So once again did YOU actually measure the distance between the corners
SURVEYOR:
Well no not in the traditional sense, I let the black box tell me the coordinates were okay to store and move on. As I'm not privy to the software code nor would be able to explain the mathematics involved, I relied on the manufacture to calculate the actual measurement, I just report what it tells me
JUDGE/ATTORNEY
So the box measured the distance, how do you know the box is correct.
SURVEYOR
Well it tells me the same answer every time. I have verified this on other jobs against conventional instruments.
JUDGE/ATTORNEY
So on those OTHER jobs the box agreed with conventional measurements, those other jobs are not why we are here, what about this job where you only used the box
SURVEYOR
well it worked great on the other jobs so it must of worked here
JUDGE?ATTORNEY
do you have an independent verification on this job that the box is correct
SURVEYOR
No, but I could go out there today and get the same answer
JUDGE?ATTORNEY
your dismissed
James Vianna, post: 382965, member: 120 wrote: I don't get the train of thought that because a position is repeatable it is accurate. You simply really don't 100% know and are assuming based on past experience. I'll use the title insurance analogy here. Title companies only go back 20 - 30 years as they rarely see problems crop up longer than that. The few times they get bit for not going back will be outweighed by the money they save doing it quickly and cheaply. RTK is no different, its a "calculated/insured risk". Whether you decide to assume this risk based on your experience or beliefs is up to you.
I am envisioning the following exchange:
JUDGE/ATTORNEY:
Please tell the court how you arrived at the distance between the two corners.
SURVEYOR:
Well I placed my new $40,000 RTK device on each corner and it told me it was okay to store the location and move on to the next point.
JUDGE?ATTORNEY
What do you mean by that
SURVEYOR
Well it averaged the location a bunch of times and the results were all with 0.10' so it must be correct
JUDGE/ATTORNEY:
So once again did YOU actually measure the distance between the corners
SURVEYOR:
Well no not in the traditional sense, I let the black box tell me the coordinates were okay to store and move on. As I'm not privy to the software code nor would be able to explain the mathematics involved, I relied on the manufacture to calculate the actual measurement, I just report what it tells me
JUDGE/ATTORNEY
So the box measured the distance, how do you know the box is correct.
SURVEYOR
Well it tells me the same answer every time. I have verified this on other jobs against conventional instruments.
JUDGE/ATTORNEY
So on those OTHER jobs the box agreed with conventional measurements, those other jobs are not why we are here, what about this job where you only used the box
SURVEYOR
well it worked great on the other jobs so it must of worked here
JUDGE?ATTORNEY
do you have an independent verification on this job that the box is correct
SURVEYOR
No, but I could go out there today and get the same answer
JUDGE?ATTORNEY
your dismissed
It seem like that exchange could be about your edm or total station, or static survey measurements in addition to an rtk measurement. It seems that the surveyor needs to be able to talk more intelligently about what s/he is doing than saying that they got the answer from the black box machine.
Robert Hill, post: 383139, member: 378 wrote: What does this represent?
The orange colored box contains the triangle parameters, The white boxes are points chosen to form the triangle, the triangle icon leads to a display of the triangle.
James Vianna, post: 382965, member: 120 wrote: I don't get the train of thought that because a position is repeatable it is accurate. You simply really don't 100% know and are assuming based on past experience. I'll use the title insurance analogy here. Title companies only go back 20 - 30 years as they rarely see problems crop up longer than that. The few times they get bit for not going back will be outweighed by the money they save doing it quickly and cheaply. RTK is no different, its a "calculated/insured risk". Whether you decide to assume this risk based on your experience or beliefs is up to you.
I am envisioning the following exchange:
JUDGE/ATTORNEY:
Please tell the court how you arrived at the distance between the two corners.
SURVEYOR:
Well I placed my new $40,000 RTK device on each corner and it told me it was okay to store the location and move on to the next point.
JUDGE?ATTORNEY
What do you mean by that
SURVEYOR
Well it averaged the location a bunch of times and the results were all with 0.10' so it must be correct
JUDGE/ATTORNEY:
So once again did YOU actually measure the distance between the corners
SURVEYOR:
Well no not in the traditional sense, I let the black box tell me the coordinates were okay to store and move on. As I'm not privy to the software code nor would be able to explain the mathematics involved, I relied on the manufacture to calculate the actual measurement, I just report what it tells me
JUDGE/ATTORNEY
So the box measured the distance, how do you know the box is correct.
SURVEYOR
Well it tells me the same answer every time. I have verified this on other jobs against conventional instruments.
JUDGE/ATTORNEY
So on those OTHER jobs the box agreed with conventional measurements, those other jobs are not why we are here, what about this job where you only used the box
SURVEYOR
well it worked great on the other jobs so it must of worked here
JUDGE?ATTORNEY
do you have an independent verification on this job that the box is correct
SURVEYOR
No, but I could go out there today and get the same answer
JUDGE?ATTORNEY
your dismissed
It seem like that exchange could be about your edm or total station, or static survey measurements in addition to an rtk measurement. It seems that the surveyor needs to be able to talk more intelligently about what s/he is doing than saying that they got the answer from the black box machine.
Sorry everyone who saw my same post 50 times
I found if I 'Post message' and it doesn't look like it posted, I do a "refresh" or whatever it's called and it gets rid of the aparrent unposted message.
A Harris, post: 383166, member: 81 wrote: Once they integrate a compass aligned with a disto into the unit, many dreams will be fulfilled.......
Leica's new CS20 has this. You can place it on a smartpole, locate a point with the GPS receiver, then using a built in disto and compass you can locate a point from that location.
As Lubos Motl has said, "95 percent is just an insignificant hint".
Reach 5-sigma and now you have something 😎
Kent McMillan, post: 383173, member: 3 wrote: Sure, of course it's a given that one can always get a more accurate result by methods other than RTK. So, the reason to use RTK isn't accuracy.
Thanks for admitting you have no practical knowledge on the subject. I know that was hard for you, but you're better for it. Emotional growth is difficult, especially for one at your age. However, trying new things, they say, keeps you young. Who knows, maybe you'll be a rabid fan of RTK, once you actually use and test the equipment.
MightyMoe, post: 383197, member: 700 wrote: As Lubos Motl has said, "95 percent is just an insignificant hint".
Reach 5-sigma and now you have something 😎
5 Sigma would indicate a problem for sure since it wouldn't be a normally distributed curve. Now 6-sigma, that's something. 🙂
Nate The Surveyor, post: 383180, member: 291 wrote: I don't think I ever want the DC and the GPS separated.
I can't understand how this this is beneficial. What do you use to run your total station? How do you shoot a point with GPS and then setup on it with TS?
When your data is very quickly placed on a thumb drive, and inserted into a DC that runs a Robot, or a Total Station, and you then work, with the robot, or Total station, your GPS can still be working. It's like having 2 crews working at once.
N
geopro_consultants, post: 383240, member: 9959 wrote: I can't understand how this this is beneficial. What do you use to run your total station? How do you shoot a point with GPS and then setup on it with TS?
Depending on your setup it allows one man to use the LS while the remaing crew work with the conventional equipment with ou. As far as setting up the total station on a gps point, use a flash drive to transfer the data from the LS to the data collector or vice versa.
Nate beat me
MightyMoe, post: 383197, member: 700 wrote: As Lubos Motl has said, "95 percent is just an insignificant hint".
Reach 5-sigma and now you have something
Actually, as any surveyor *should* know, normally distributed errors tail off so much beyond the 2-sigma, 95% confidence levels that for purposes of land surveying the 95% confidence levels are certainty. Naturally, an increase to the 3-sigma level (an uncertainty only 50% greater) takes in 99.7% of all errors, which is why the 95% confidence level is useful and can be considered to be certainty for practical land surveying work.
Kris Morgan, post: 383213, member: 29 wrote: Thanks for admitting you have no practical knowledge on the subject.
LOL! If you want to claim that you can make a survey more accurately via RTK than via any other surveying technology, be my guest. That would be more fun to watch if you weren't a Texas licensee, though.
Nate The Surveyor, post: 383243, member: 291 wrote: It's like having 2 crews working at once.
N
Ugh.. this seems incredibly sloppy way of doing it. Each time you copy coordinates from one device to another is an opportunity to introduce corruption. I hope your coordinate transfers are carrying a checksum value with them.
I'll stick to our method of having one data-collector to rule them all (GPS and Robot).
Kent McMillan, post: 383143, member: 3 wrote: The real value in adjusting vectors derived by GNSS methods is to lift the curtain on the black box and to determine what the actual uncertainties in the vectors are and to test process consistency (which has reliability implications), so that the uncertainties in quantities derived from those vectors can be realistically estimated. When one is working to a specification with survey accuracy provisions like those of the ALTA/NSPS, the standard way to demonstrate compliance with the specification is by uncertainty analysis via a least squares adjustment, and that requires dealing with GNSS vectors as stochastic quantities.
If one is using RTK as a magic box, all he or she gets is numbers, all of which are wrong by varying amounts and from which bearings and distances are computed that contain even greater errors of varying magnitudes. Without a powerful way of estimating the way in which the errors propagate through the survey results, that's just a drafting exercise.
I am aware of all that. What I have trouble with is the idea or a method of applying it to rtk. In a static network it would be usual to have all stations similar in that observation times are alike and physical environments are all picked for good sky view with little or no multipath. Therefore you can get a realistic random error. Multipath being the greatest random error, and differing considerably from one rtk position to another, I'm not sure that least squares including all those in a network is a realistic representation. I question the "standard" way being applied to rtk positions, they simply don't have the commonality required for the analysis. It seems to me it would be like pacing some lines and edming others and including all in the analysis. I don't have an alternate way other than relying on the built in algorithms to provide a truthful error estimate for individual measurements. there are redundant measurements, least squares and other algorithms being applied in gaining an rtk position, so it's not without science behind it. But it does in a way bring us back before edm's to chain/tape like days that requires some skill of operation, although a much more complicated skill.
As far as ALTA's go, I've heard rumors there might be those providing them that don't use and know nothing about this least squares thing. I'm not one of them.
OK, but it works, and it works well.
N
Nate The Surveyor, post: 383243, member: 291 wrote: When your data is very quickly placed on a thumb drive, and inserted into a DC that runs a Robot, or a Total Station, and you then work, with the robot, or Total station, your GPS can still be working. It's like having 2 crews working at once.
N
I have to do this often in the field we have several different GPS brands, if I am using the JAVAD I can use the Carlson Surveyor + data collector for everything, run the JAVAD then with the Total Station no need to change jobs or transfer points. If I am using the LECIA GPS I have to use a flash drive to switch points to the Carlson Surveyor + before I can use the Total Station. I prefer to use the JAVAD GPS and not have to transfer points, but it only takes 2 mins to transfer points. Nate is correct some times having two crews working does save a day in the field one man on the GPS another with the total station.
I am thinking about getting a LEICA total station, which would eliminate having to transfer points with the LEICA GPS unit.
I tell my clients all the time that I'm 5% uncertain, makes them feel so good.
