need to vent...

Andy

The folks (I hesitate to even call them surveyors) that get desperate enough to perform cut-throat and substandard work are usually soon gone.

I know, not quick enough, though.

In my career I've watched their numbers rise and fall. I look at their work and pricing as 'dying quivers'. They'll soon be broke and wash out to something else.

Stick by your guns and your professionalism. You will get to get wear that badge as proudly as the silver hair that comes with it. Just stick it out.

edit:

No pun intended on the hair comment..;-)

Back in the late 1970's there were a couple storm events in metropolitan New Orleans in which hundreds of homes were damaged due to flood waters. Most of the damaged homes had flood insurance, and the surveyed elevations were based on municipal benchmarks that were not part of the National Spatial Reference System of the National Geodetic Survey. (They had conveniently "higher elevations" than NGS marks.)

The Federal Justice Department sued the Parishes (counties) and the Surveyors that did the certificates for some $96 million in Jefferson Parish and for $46 million in St. Bernard Parish.

After that fiasco, everybody got religion.

Have faith, they'll get their just deserves ...

I like cleaning up messes. The fees are greater.

I have forgotten what it was like to not be continually cleaning up the messes created by a few "surveyors". But, then again, it is a living, and someone has to do it.

or you could...

give up, thanks for the money. 😛

I feel your pain. I have seen an influx of surveys with worse accuracy with the advent of RTK than I ever did during the EDM era. That first magical number is always correct regardless of trees, buildings, multipath, poor satellite geometry, etc. Don't even attempt to get multiple readings as a check. I've retraced surveyors who RTK in property corners 10 feet apart that were off 0.2'. Close enough when few seem to care anymore.

We use RTK for most of our FEMA jobs. We used to check in to benchmarks but after about 50+ check ins with less than 0.03' we started just hitting the control in the morning and again in the afternoon. The only ones we had discrepancies with were the ones that had not been observed with GPS previously. Considering that the FEMA mapping around here is in 88 the RTK is probably more accurate than that old benchmark.

We schedule a bunch in a day, send one guy out with the RTK to set control at each site, then have another guy with a robot do the EL Cert or LOMA at each site. The guy with the RTK swings around again in the afternoon to hit each control point. 95% of the time they are with in 0.02'. If they are over a tenth or if the BFE and LAG are close we hit them again a few times over the next day or two to average them out Sometimes the BFE and LAG are far enough apart that a tenth won't make a difference.

To run from a benchmark around here would take days of level runs or traverse.

Also we give no less than 60sec observation on a control point.

Tom

I feel your pain. I just shake my head at the guys using RTK to Stake all but flat Storm/Sanitary Sewer. RTK is a tool, not God.

With that kind of frustration level, if you lose a project to some monkey and then have to come back and clean it up - the price goes WAY UP.
"Should have stuck with me in the first place!"
That would be my attitude.

I've had to clean up several software projects in my days. They got assigned to someone else and then assigned to me when either they f..ked it up or couldn't handle it. "Should have just given it me in the first place!"

> I have seen an influx of surveys with worse accuracy with the advent of RTK than I ever did during the EDM era.

That is pretty much my experience. There are so few folks using RTK properly that the presumption that an RTK boundary survey will fail to meet minimum technical standards is usually justified. The sexy idea that everything can be done on a run with modern technology has somehow taken hold in some offices as SOP. Digging for buried monuments is much too time consuming as is conventional traverse in obstructed areas.

The sorts of RTK FUBARiffic surveys I've seen over the years would make a nice monograph if for no other reason than to let posterity know what happened in the early days of RTK.

I kinda doubt that your 60 seconds is any better than the first second.

RTK is real-time. It doesn't keep a running average. For efficiency's sake we'd like to think so, and many a salesdroid will tell you so, but it's not their stamp.

If you are averaging several RTK shots taken moments apart it just gives a false confidence. It seems to repeat pretty closely, & if you average them or least-squares them by themselves the math says the error ellipse is smaller thanks to sigma/sqrt(n,) but it is not the same as averaging shots taken under different constellations.

Andy

> The folks (I hesitate to even call them surveyors) that get desperate enough to perform cut-throat and substandard work are usually soon gone.
>
> I know, not quick enough, though.
>
> In my career I've watched their numbers rise and fall. I look at their work and pricing as 'dying quivers'. They'll soon be broke and wash out to something else.
>
> Stick by your guns and your professionalism. You will get to get wear that badge as proudly as the silver hair that comes with it. Just stick it out.
>
> edit:
>
> No pun intended on the hair comment..;-)

:good:

100% correct about not averaging different constellations. But its still averaging the shots of that observation. Maybe it's false hope but I have observed more accurate readings when checking with the total station if the RTK observation is longer.

We head back later to check under a different constellation. I understand that its just a spot check but considering that FEMA is tenth accurate we're usually plenty good. If I had to run something more rigorous, say for a long traverse or construction layout, I would run static and process it from there.

Tom

> I kinda doubt that your 60 seconds is any better than the first second.
>
> RTK is real-time. It doesn't keep a running average. For efficiency's sake we'd like to think so, and many a salesdroid will tell you so, but it's not their stamp.
>
> If you are averaging several RTK shots taken moments apart it just gives a false confidence. It seems to repeat pretty closely, & if you average them or least-squares them by themselves the math says the error ellipse is smaller thanks to sigma/sqrt(n,) but it is not the same as averaging shots taken under different constellations.

I am currently working on a topo of a road centerline so I can fit an alignment to it and describe it. This is Forest land.

It was suggested that I just break out the RTK and do it fast. I might get 20% of it with RTK but mostly the canopy is too thick.

There is this weird compulsion to do things with RTK in a day which really requires a week with Total Station and would've taken 6 weeks with transit and chain 50 years ago. My work will be used for the next hundred years, why not take a week and do it right? I am doing it right.

Meanwhile every product seems to be getting cheaper so we pay the same dollars that we paid 20 years ago so a few corporate CEOs can get rich.

It's all about how you use it and and what the required accuracy is. We are working something with about 90% canopy...4 miles of clearing limits no elevation. I asked the PM and GC how accurate the limit stakes needed to be and they said 5 feet (yes I have that in writing). We already bid the job as lump sum and won it planning on using a total station and two man crew.

After hearing the 5 foot requirement we took out the ol' sub foot GIS unit we use for wetland flags. Did a few tests in the woods up there and compared them to some total station control. The results were well within tolerance so on Monday I send one guy out there with a mapping grade GPS and some flags to finish the job in 1/4 the time with half the manpower. We'll spot check a few areas from existing control for QA/QC and hit some of the already done areas on a different time of day to check under different constellations.

There's a time and place to use this technology...the key is to know when to use what...

Tom

I think the GIS grade stuff is better than the survey grade stuff in the low accuracy type of work.

So you are doing right there.

I just find all of this false hurry strange.

Clearing limits is one thing but a property description that will be around for hundreds of years is another and an extra week is really insignificant.

On a big site where you are there every day, you can essentially monitor your own control with the RTK and have a better idea of what's going on over time. Same with municipal entities -- they've got the time and the budget, so they can hit the points on different days and under different constellations and manage the data.

A small shop, or a solo surveyor, might not have the budget, the time, the procedure, or the basic knowledge, other than what they learned from the sales guys, to make those redundant checks. Whole different game, if you are only visiting a site once or twice hoping to topo it, stake it, draw it, record it.

If the big company (or a municipality) gets bit by RTK, they just send the crew back to do it over. They made enough on the other 99 jobs made possible by the RTK efficiency to cover it. There's insurance for any damages. A smaller company or a solo practitioner doesn't have that kind of slack. Both kinds of surveyors post & read here, and I just want to point out to the more independent types that RTK is a tool that can't really check itself, except with redundancy over time. And, although making a mess with RTK is equal-opportunity with regard to company size, the smaller shops are less likely to catch the blunders.

If the crew hits 5-6 monuments going around the block in an hour, it's all essentially the same constellation. Averaging 2-3 shots on each point within that hour makes the relative distances a little tighter, maybe. If the geometry of the constellation doesn't change much while you are on site, the distances may all check pretty well -- you may have a nice square figure with no other checks, but it also may have a systematic offset of a couple tenths georeference-wise from what you would get with fast static or with averaging "different-day-different-constellation" RTK shots.

If you are there when the "surf's up" (geometry changes, SVs rising or setting) on the DOP graphs of your mission planning, (pick your flavor, I usually go by GDOP, if you are messing with elevations, look at VDOP) you could get funny results, one end of the job has a distance that checks, so does the other end, but the stuff shot while the DOPs were changing is off a couple tenths.

no benchloop for a flood cert?

it's been a while since I did a flood cert, but to not complete a benchloop run with a level seems to me to be out of compliance. maybe the rules have changed.....