Aloha, is it a common practice among the surveyors to save it as new point? Even if you utilize the same BS point repeatedly through out the project...
If yes, I am guessing it is simply for verification or are there other uses of this repeated collection of the same BS point?
I am trying refine my work flow and want to emulate what the pros do. 🙂
Thank you
We collect the back sight as a check at the beginning and end of every setup. If the gun is in the same spot for several hundred points we grab a shot every hundred points or so. It makes catching and correcting problems easier.
I had an instrument man that would store a new number everytime he shot a backsight or would shoot known points as a check.
All it did was create a load of point numbers for the same point with coordinates that fall within the size of a BB or at most a dime.
When it was loaded into cad it was a nighmare to distinguish a point's number with a wad of numbers in the same place and each one has a description of HUB#7.
The only time I store a known point with a new point number is when it is used to close a traverse.
I will use stake to point and take a shot on the point to see if I am shooting the correct point and to check myself and the setup at each end.
The results will let me know if everything is good to go. I just never store a new number.
That is my take 😉
yswami if you are setting out from a known control point and using a a known back sight BS control point I periodically "set out" out the BS to ensure that the tripod is firm as the software displays the delta x,y and z, If you see a horizontal creep in delta x, the BS azimuth then depending on your instrument time to reset BS azimuth.
I usually add a letter to an existing control station number, so when subsequently tying into one of the control points that identifier is retained as a point. If you can see a lot of control points you can number a previously observed point say originally 7, so then then add say A then add station observed from say 2 so recorded tie becomes 7A2.
RADU
We do not store the back sight .. But the raw file holds all the information from the back sight .if you need to ever fix something it's there ..we use the raw file to generate points in the office.. Point point file from the data collector is unused .
We store the back site check shots with their own F2F code. They come into the drawing in a separate layer and the person processing the data can take a quick look to make sure there aren't any obvious blunders, then just turn the layer off and move on.
> We store the back site check shots with their own F2F code. They come into the drawing in a separate layer and the person processing the data can take a quick look to make sure there aren't any obvious blunders, then just turn the layer off and move on.
I like to store them all too. I find it easier than sifting through the raw file. I set up my field book with 4 columns.
Shot type Point # H.I. Description
TO 1001 1.300 Caissons
QC 1075 0.100 BS Check
LO 1076 0.100 Anchor bolt
QC 1099 0.100 BS Check
LO 1100 0.100 Anchor bolt
QC 1123 0.100 BS Check
TO means topo, QC, quality control and LO layout. It gets pretty easy to go over the surveyed data.
Sorry about the column formatting, not too sure how to make it pretty.
The software has a pretty useful command to move point attributes, so not much of an issue to have multiple shots on basically the same point, +/- dust.
If I recall from your previous posts, you're running TDS survey pro. If that's the case there is a built in check BS function within all the routines which doesn't require a sideshot. I don't remember if you have to store it but it is definitely in the raw data.
1 point, 1 point number.
I store checks as the same number.
Must be the same as with Trimble Access,
we use the check Backsight button, no additional point is stored but in the job file a check backsight record is stored with all the raw data and the deltas. When we download to our office software we get a good looking report with all traverse observations and backsight data. works very wel for us.
Chr.
🙂 :good:
> All it did was create a load of point numbers for the same point with coordinates that fall within the size of a BB or at most a dime.
:-/ :bad:
As James Fleming describes below, use your F2F to send the check shots to a check shot layer. Then keep that layer turned off except when checking your check shots.
During the last 3 month I have discovered 2 major (3' +/-) busts in topo data because of check shots.
> When it was loaded into cad it was a nightmare to distinguish a point's number with a wad of numbers in the same place and each one has a description of HUB#7.
>
That could have been avoided if they had described the check shots differently.
😉
Back sight checks are free. Take them all you want. They don't have to be recorded. On a backsight check I'd just tell the party chief on the radio of the results. We (at any engineering/surveyor thing) never recorded our shots on BS checks.
That was doing simple field checks. If we got a bad shot, we would either setup somewhere else or just re-setup the gun with a new HI and stuff. Perhaps my eyeballs weren't working so good that day. Who knows? If a check fell out of tolerances we dealt with it in the field and noted it in the book.
I only want a point to have an original point number and a closing point number when used so.
Point 7 will always be HUB#7 even when it is closing point number 45 on point 7, it is still HUB#7.
When checking into a known point, there is no reason to give it a new point number unless it has changed position by some means like some big yellow machine ran over it, and it does not rest in its original position. Then there would not be any HUB#7 anymore.
The first point cloud I ever saw was one day when I pulled a job into CAD and many points had a clouded cluster of dozens of numbers.
Turned out every morning on a project and thruout the days, setup on a control point and back sight a control point and a new point was given to the back sight and setup locations every time a check was made, never checking in the field that they were even the right points or point numbers.
I was told that it was so I could see what they had done. Raw data will tell me everything that occurs while it is connected. (It is the computations that are done off book that will get you in the end.)
Then in an absent minded act, raw data showed that for the same two points, different point numbers were beginning to be used for the same control point HUB#7 and all the while applying new point numbers to the previous new point numbers.
Don't even bring up the fact sometimes HUB#7 was actually HUB#10 or other #.
I take a check shot and compare it to the control information before proceeding, and don't ever, ever, ever assume I shot the right points and then expect some raw data guru will figure it out.
That is overkill for me.
Keep it simple, Once control is established, one number for every point is enough.
Make your checks and record them how they suit you because we all use some method to find that 3ft error and when found we are satisfied with the results and we can sleep at night.
Bottom line is when it all goes to print and your name and seal is applied, the client or whoever receives the information does not care about the method.
The results are all that matters.
😉
> I take a check shot and compare it to the control information before proceeding, and don't ever, ever, ever assume I shot the right points and then expect some raw data guru will figure it out.
We may be talking past one another. Once you have established a control coordinate on pt#7 that indeed should not change. When you set up and backsight it again you do not re-record a shot on pt#7 as pt#7. But you record a check shot to point 7, using whatever point number you may care to - which mayhap be pt 45. And you descriptor that point as being a check shot. That way there is a record in your data set that proves you were set up right, and one that will be present if you are obliged to recalc the data set.
There should be a similar such point at the end of the data set, and there should be at least one check to some point other than the backsight somewhere in the data as well.
It's not enough for you to know that your data is right. You may have to prove it some day. At that point your word and your reputation will not be enough to get it done.
Keep it simple, don't go beyond the scope of methods of collecting data.
When it becomes a matter of being right, proving myself right is not the question or the answer, it is a fact.
Any other findings would be incorrect and checking their work would show their errors.
The last thing anyone wants to see or use in proof of their work is the raw data.
The raw data is what got you to your final product.
The final product is the only proof you want to offer.
IT shows where everything is as you have found it to be and you want it to be repeatable by whatever means, not by your raw data only.
Meet in the location and prove what is and is not.
Use their control points to prove their errors, that is the real test.
Being called on the carpet and told that your data is not reliable because it looks too good to be true is a sign that you need to look for a new job.
B-)
> The last thing anyone wants to see or use in proof of their work is the raw data.
:-S
> > The last thing anyone wants to see or use in proof of their work is the raw data.
> :-S
He maybe meaning that, at times, the raw data needs editing/clean up (wrong backsight rod height, code, point number, etc) Hence, it could be difficult to use for presentation purposes.
My only concern in re-using the same point number over and over would be a conflict in point class. Is the point that you are selecting the original, one of the observations or an average of all observations.
The Leica users probably know what I am talking about.
That is why if I use a control point #1. No other points are called #1. The reference to #1 will be in the description as mentioned.
