Angleo
I'm sure that you're not insinuating that Leon didn't attempt to get them to do it right the first time. The man does, from all accounts, try to get it right the first time.
Now, that being said, I've mapped hundreds of miles of pipelines with submeter equipment because the client didn't want to pay for a survey grade location. However, when they needed survey grade location of those pipelines, they paid me to do it again.
Most of the time I was within 2 feet of the pipe though.
The only thing that I would add is that I would have something in writing that explains the accuracy of the equipment and the prospective end users in mind. That covers your butt when it bites you.
With that explanation a CORS might not work so well if it's set to 30 seconds. CORS that are also used for RTN should be set to 1 second or less so you would need to find one of them. To be able to collect a lot of data in a short time period I don't think longer than a few second occupations will work for them. They probably either need to get real sub-meter/foot GIS/GPS equipment or stick to RTK and the hassle of the base station.
I tried the PPK one day when all the radio channels were taken and I couldn't go RTK. So I set it up using the defaults. I just went to work when it told me I was fixed and moved to the next point when the rover told me I had the point (just a few epochs). I was doing a railroad track (out of service at the time). When I processed the data I could see that the tangents were not very true so I went back later and did it on a weekend when the RTK was good. Some of the PPK points were out about 10 cm. So sub meter yes but not good enough for what I wanted.
I'll actually lose here as I been renting them a base for RTK. Dollars are tight these days. Like I said I was just trying to help a friend get some answers to his questions. I'm not the expert he needed so I was asking others. Thanks to those that gave some good answers.
Hang on Kent
I've staked miles and miles for clearing for pipelines with submeter. When they're going to take a 30 to 50' swath of trees out, centimeter or sub foot doesn't matter much. It's cost effective and allows you to work in other markets.
For as-builts, it all depends on what the end user wants and is willing to pay for. So long as I'm generating GIS files for T4 maps at the RRC which go on quad sheets, 1 foot or 10 feet is tough to see.
For easements though, I totally agree. However, I've staked pipelines with submeters that were going to use easements, and then came back and survey grade as-built them and wrote the easements based on that survey and then they filed the as-built.
If your license isn't on the line, then submeter is fine.
We had very good luck with 30 second observations for obtaining sub-foot by post processing against the CORS stations.
Hang on Kent
> I've staked miles and miles for clearing for pipelines with submeter. When they're going to take a 30 to 50' swath of trees out, centimeter or sub foot doesn't matter much. It's cost effective and allows you to work in other markets.
Leon was asking about placing fiber-optic cable, probably in an area with more sagebrush than anything.
> For easements though, I totally agree. However, I've staked pipelines with submeters that were going to use easements, and then came back and survey grade as-built them and wrote the easements based on that survey and then they filed the as-built.
Well, next time just turn the whole exercise over to some engineers with one rover and hope for the best. I mean with modern technology it costs waaaay too much to actually get accurate as-laid positions on fiber-optic cable in country where GPS positioning methods can be easily used. I mean, you'd probably be looking at an additional $100 per mile and who would be able to afford that?
Angleo
> Now, that being said, I've mapped hundreds of miles of pipelines with submeter equipment because the client didn't want to pay for a survey grade location.
That is puzzling. Sub-meter/ centimeter. Same equipment, same price.
I have also surveyed hundreds of miles of pipeline. I've never had a client ask for a price difference between sub-meter and centimeter work. I've never had an oil and gas client ask to create a blanket easement in this day and age. Blanket easements are the purveys of unethical lawyers; accepted by unscrupulous land owners and prized by cheapskate pipeline owners.
I'm a surveyor. Whether I'm using a network rover or RTK, it is always centimeter work. Waas, DGPS and Omnistar are used only when I am offshore or mapping a watercourse and have no other choice.
AS3
Adam
You do it your way, and I'll do it mine.
Some time ago I rented units to the county to inventory the county roads. They didn't want to set up RTK bases over and over, and at the time the GPS signals were scrambled. We worked out a mount for their truck and put a unit on it. Then the engineer would drive the roads using continous topo in PPK mode, taking shots at 15 second intervals. I post processed the data using a base that was set up at the office. I can tell you that the results were great. Even the roads that are 70 miles away ended up with really tight locations. Over the years I've compared the points and I see elevations within 0.15' and horizontally they look good; it's hard to pinpoint where the shot was taked horizontally since it was random and he stopped only for culvert and cattlegard crossings.
But these locations are much tighter than sub-meter; it's just a matter of technique.
And they were collected as a timed shots, just a moment in time. The key is to have a long fixed session.
Adam
Is that the equivalent of taking your ball and going home? Or, Na Nana Na boo boo, Stick your head in ...; or even, I'm rubber and your glue, everything you say bounces off of me and sticks onto you.
The issue is a serious one. We are fastly approaching oblivion as an industry and need to educate our clients about the importance of obtaining geospatial accuracy and precision to the centimeter level at all stages of planning and development regardless of its end use, and why the data collection and measurement methods used by professional surveyors are more benifical as opposed to GISers' "sub-meter" methods.
GISers may understand the operability of relational and hierarchical databases beneath map layers, but very few understand the need for integrity of geospatial data.
We need to control our own destiny and in order to do that we need to stop peddling a so-called "cheaper" service, when the only difference between the two is the cost of the equipment, especially when the field procedures are almost identical.
I know... I know..., "You do it your way, and I'll do it mine". How visionay.
AS3
Yes Adam , you're right
Who are our clients to question what kind of data we give them. Who the hell do they think they are knowing who all of their end users are while we don't. Why don't clients bend to the will of those of whom the employ as contractors.
You're right! We should start an ad-campaign whereby we insult and alienate our demographic by belittling them and explaining we know better than they ever will. Our slogan could be "We're from the survey, er geospatial office and we're here to help."
See, in the previous statement I made to you, I was trying to take the high road, but once again you've proved that old maxim
Angleo
No reflection on Leon......but my advice would have been spend the $$$$ and do it right the first time.
What's the old saying?......."you can have it quick, cheap or good, but only two out of the three."
"I've mapped hundreds of miles of pipelines with submeter equipment because the client didn't want to pay for a survey grade location. However, when they needed survey grade location of those pipelines, they paid me to do it again."
Switch Leon's "fiber optic cable" to "oil pipeline" and maybe the dangers of mislocation, even by as little as two feet, become apparent. Recent pipeline explosions due to digging in the area of older pipelines have been in the news often over the past few years.
From a business and liability point of view, get it mapped, and get it mapped right, when it goes into the ground.
Angleo
I won't discount what you're saying, but you can only do what your clients will let you do.
For us, there is a difference in price for submeter and RTK due to the extra receiver charge. It boiled down to money in the end.
High Road?
Really? You would call that statement taking the high road?
> You're right! We should start an ad-campaign whereby we insult and alienate our demographic by belittling them and explaining we know better than they ever will. Our slogan could be "We're from the survey, er geospatial office and we're here to help."
Since when does educating a client become construed as insulting and alienating them? Clients hire experts because they are not experts themselves.
I think your disdain for me as a person is clouding your judgment of the issue, which is "why use survey grade all the time?”
AS3
Adam
No, my disdain for you has nothing to do with providing the client with data they ask for. That's just good business.
Rtk = 2 receivers in redneck USA which costs more than 1 receiver.
You can educate a client to the point they go to another vendor who gives them the data they ask for.
Whatever. I'm not arguing with you any more.
Sub-meter Engineers
> I would just say that much of this sort of work has never been done by surveyors but by staff at the utility companies using whatever tools were available to them. >
>
Exactly right. I did a short stint with a natural gas pipeline/distribution company in MI in the early 80s. Much of their surveying was done with a handheld Suunto and a 300' steel tape, spliced in several locations, laid on the ground in a relatively straight line along the compass bearing. These "surveys" provided the basis for preliminary design and for easement descriptions. They broke out the 1' transit for as-builts.
I would say that sub-meter GPS in the middle of nowhere is leaps and bounds ahead of that work.
Adam
In Texas, most surveying companies (who itemize their services) have an average daily rate for a GPS receiver pegged @ +/- $300.
Yea... like an oil and gas client who has do deal with a constant barage of regulation from FERC and the Railroad Commission is going to seek another vendor because he won't fork over an additional $300 a day. NOT.
It is good you are not going to argue with me anymore, because you know a contract is not going to be lost with an oil and gas company over $300. Oh, and because you know that I am right.
AS3
Angleo
To the utility companies, it is always about the money and who gets it. Some are deserving and some or not.
Was told yesterday by an engineer that he had never met a Surveyor that was worth $50,000 a year.
I am competing against an in house guy that uses a measuring wheel and a compass for his field equipment because that is good enough for their easement work. I question their decision on their methods and results constantly.
Angleo
> What's the old saying?......."you can have it quick, cheap or good, but only two out of the three."
>
You can have it quick and cheap, but it won't be good. Or you can have it quick and good, but it won't be cheap. Or you can have it cheap and good, but it won't be quick...
Did you ever get a real answer?
This can be easily done by creating a new survey style. Just copy your RTK style and name it something like WAAS....then go to Survey Styles and edit your new one. Only change you should have to make is under Rover Options>Survey Type. Change this to RT Differential. Then change the Broadcast Format to WAAS.
This should work fine.
I usually see < 10 foot horizontal accuracy.
Did you ever get a real answer?
I found this one on Amazon.
http://www.amazon.com/gp/offer-listing/B00355N1LM/ref=dp_olp_0?ie=UTF8&redirect=true&condition=all
