minimum technical standards
> ... the engineer who did the topo ...
Okay, you've got "engineer" and "RTK" in the same narrative and it's suddenly an OPUS problem? :>
C'mon, MM!
MM,
"The engineer disregarded existing control, set up his base one day, collected the topo info, went back to his office, did an OPUS solution on his base and reduced his topo data and designed the reservoirs."
I've told you a million times--don't exaggerate. Let's recap:
1. Didn't use or tie any of the control.
2. No Projection, No Datum on a SPCS job.
3. No point set.
4. Somehow used OPUS, pointlessly.(That's a pun.)
5. Used a bogus topo (in your opinion) to design a reservoir.
Where you at, Moe? Sounds like there's a crying need for competent surveyors.
Dave
GO KENT!
Less than 300 posts to go to second place!
C'mon, MM!
yep! there is sometimes! If only it was the first time
minimum technical standards
lol, usually a topo with GPS is RTK, locating the points with Static would probably take a couple of years to do to get the points, and I didn't say it was an OPUS problem, I said it was a misuse of OPUS problem.
Just like a misuse of RTK can cause issues.
C'mon, MM!
Did it hold water?
C'mon, MM!
For a decade more or less, i think they are mostly reclaimed now.
> I would use them more if they would share their logs and give an independent source of information.
What would you do with it? If you had vectors (which aren't really raw) you could use StarNet to analyze the closure.
If you had a RINEX file, you could post process, which would be good.
Is that your intention?
For the most part RTK like OPUS or your EDM, is a black box, in that the truly raw data doesn't mean much to most of us.
The important intention is that I have them to include in the job file.
Whether I use them or not, they are a part of the job.
The whole idea of someone not giving up all files that were created for any job leads to doubt.
Why do they only want to give final coords and not raw data or other digital information that led to coords?
What are these guys hiding?
I know I'm not the only person to go out years later and find that something is not in the position that it was reported to be in.
Without all the data, how can checks and balances be made?
Wow, I'm surprised how this thread has taken legs.
For my 2¢ worth, I totally agree about it all being in the "Metadata". I don't have a problem with some surveyor doing what he thought was right back in 1996. If he collected data on all of his control and then rotated it by the convergence angle to get to some kind of "mean true north" for where he was working, then so be it. Mainly he should have spelled out how he got there. That was my thinking back in the early '90s. I didn't know what "metadata" meant, but I put down enough information for someone to be able to take a calculator and go from my local database back to State Plane Coordinates and/or even to latitudes and longitudes.
Back then (and even today for that matter) there was no "protocol" on what to do with state plane coordinates when you got them. In this state there was (and is) a defined "origin" in the statutes. A lot of guys felt that they should scale up their coordinates to a project coordinate base by radiating about the statute "origin". Many guys also rotated their coordinate base about the same origin to a "true north" bearing base. Others might have rotated about the central point of their project. Many others left their data in a "state plane" bearing base (while still applying a "combined factor").
The best thing they could have done is leave enough of a trail to state how they did whatever they did so that someone could reproduce their work (or take their work to "state plane" and work with it from there).
Many times it takes some real detective work to try to find out what they did back then based on not-so-explicit metadata. As a matter of fact, I just found an old control that we were scratching our heads as to how they got to their local project coordinate base around the same time (1996) and it occured to me that that was in the general time-frame when Colorado changed a statute to state that we would start working in "us-survey feet". Prior to that the metric state plane coordinates were multiplied by the "international foot" factor. When we applied that factor to the state plane coordinates, we were able to match the published coordinates.
Sorry for the long post and ramblings. I don't follow a lot of where this thread has gone. But the old surveys that are the easiest to retrace are the ones where a good supply of metadata was provided.
As a matter of fact, I just found an old control that we were scratching our heads as to how they got to their local project coordinate base around the same time (1996) and it occured to me that that was in the general time-frame when Colorado changed a statute to state that we would start working in "us-survey feet". Prior to that the metric state plane coordinates were multiplied by the "international foot" factor
hehe, that international foot/survey foot thing can cause all kinds of havoc.;-)
Encounters with Metadata of the Third Kind
> Wow, I'm surprised how this thread has taken legs.
Why? The whole topic is material fit for a 21st-century version of A.C. Mulford's "Boundaries and Landmarks".
The really interesting problem is how to determine exactly what sort of a clusterfuge one is dealing with, and as far ahead of time as possible. In that light, there really are fundamentally three kinds of metadata statements. Metadata of the first kind is a statement that accurately describes what was done. Metadata of the second kind is metadata that makes sense and appears to describe what was done, but doesn't. Then there is the third kind, which is metadata that upon its face indicates that the author didn't know what he or she was doing and that puts the whole effort into another category entirely.
Recognizing close encounters with metadata of the third kind is what I find most interesting.
Kent, Don't Be Offended, But...
> > So a bearing of S43-27-19E wouldn't be a grid bearing then, since it refers to Grid South? I'll stand by what I said, Bearings refer to a Grid System.
>
> You might have a point if Grid North were not a unique direction at every point in the projection zone of the SPCS. There is absolutely no ambiguity to saying that a particular bearing refers to Grid North of the Texas Coordinate System of 1983 (North Central Zone). Naturally Grid South refers to Grid North as a trivial case.
>
>
> > "Well, the purpose of that part of the metadata is to give some idea of accuracy and reliability. How do you propose to do that if not by mentioning the duration and number of the sessions and the fact that they were on different days?"
> >
> > Just add this to the metadata:
> > "I, , am accurate and reliable, and I have a clue."
>
> If that were sufficient, there would be no such thing as a bum survey. :>
>
> With static GPS, all other things being equal, the determinants are :
>
> - session duration,
> - redundancy, and
> - proficiency.
>
> More than one session on more than one day tells me that someone was serious about what they were doing.
I like my statement. It give the data and you at least agree to that as you didn't add anything, only re-word it. However, you note session duration. If my connection to the grid is by OPUS, it implies at least a 2 hour duration (possibly longer). Had I noted OPUS-RS, that would have also noted a duration of less than 2 hours, but more than 15 minutes.
At this point, it's splitting hairs. Shawn Billings is VERY close to your and he and I agree that retracing each others work with our variation of metadata is easy and as you say, requires no mental heavy lifting. 🙂
David
> Kris,
>
> I like that! We'll have to see if Kent approves.
> 
>
> Dave
It should be noted that I change that occasionally when Gamma deviates more than 15" (my arbitrary number) across the tract. When that is the case, I give an angle of convergence and a combined scale factor at one point which is typically my POB.
David
> Kris,
>
> I like that! We'll have to see if Kent approves.
>
>
> Dave
Also, my statement is a variant from years ago about arguing this. While NAD83 bearings are, essentially, the same regardless of what realization you are working in, the coordinates are not and it became VERY apparent that one needed to state WHAT variant/realization of NAD83 one was working in. At that point, it also became apparent that the method for connecting to the grid was equally as important (i.e. classical observations/GPS observations, HARN/OPUS/Tri-Stations).
I like to work on the grid. All of my work is on the grid. My CSF's do not change acreage enough where it becomes necessary to bring it up to surface, although I have a method of doing that that does not molest the coordinates either. My good buddy Shawn has the same line of thinking that Kent does insomuch as they think that I'm silly for reporting Grid distances when EVERYTHING we do measures surface.
My standard answer is that I could screw up a train wreck and it's one more way for me to not harm myself. 🙂
Encounters with Metadata of the Third Kind
> > Wow, I'm surprised how this thread has taken legs.
>
> Why? The whole topic is material fit for a 21st-century version of A.C. Mulford's "Boundaries and Landmarks".
Why indeed. Basically you are correct because you are not surprised it "took legs". The reason I am surprised, is because I would have thought that (a) everyone who uses GPS would agree that adequate metadata is important in order for your work to be retraced, and (b) that even most of those that don't provide adequate metadata think they do (or at least say they do).
Encounters with Metadata of the Third Kind
> The reason I am surprised, is because I would have thought that (a) everyone who uses GPS would agree that adequate metadata is important in order for your work to be retraced, and (b) that even most of those that don't provide adequate metadata think they do (or at least say they do).
I'm not sure that properly accounts for a statement like:
"Bearings refer to GPS North obtained with Trimble RTK on [date}"
Encounters with Metadata of the Third Kind
"Bearings refer to GPS North obtained with Trimble RTK on [date}"
I see that one a lot, or variations of it.
I also like "Bearings are assumed but relative."
Actually the second one tells me more.
Encounters with Metadata of the Third Kind
> "Bearings refer to GPS North obtained with Trimble RTK on [date}"
The purpose of that statement is to tell you absolutely everything they know about their data so that you will know precisely to what extent you can use and rely on the information.
They may have accomplished their purpose...:-P
Interesting discussion.
But what about the basics?
What Record Monuments did you tie to?
What Record Coordinate Values were used for those Monuments?
My scan of the posts and replies... it seems nobody mentions the Basics!
after you get that foundation laid then you can go on to say what procedures you used to derive your new values (via your black box, OPUS, transit & chain, magic... whatever)