I don't know if this is the best place for this and it won't be the only place I reach out to on it so no worries if it's not.?ÿ I'm a licensed contractor with a tech degree in civil engineering.?ÿ I worked in structural CAD 11 years and as CAD manager for an innovative civil consulting firm for 13 years.?ÿ There I had many data transactions with surveying firms, we surveyed as needed for design on large projects throughout the southwest US and I was deployed as a field engineer on many of them, which included grade staking, feature location and as built surveys - always set up prior by licensed or other professionals, so I was basically a data collector, communicator and map maker on those projects.?ÿ I got very interested in surveying and, besides the classes I took for the tech degree years prior I began taking a 2 year survey course offered by a local community college.?ÿ The following year I was "called" to move, which cut that course short but I did learn a lot and got some great resources.
The owner of the consulting firm is licensed and vouched for my abilities with his firm to take the FS, which I studied too long for and passed in March.?ÿ I don't think I'm worried about passing the PS.?ÿ I'm reviewing areas of knowledge and reading through Brown's boundary control again slowly.?ÿ What I am worried about is not really knowing what the hell I'm doing...
Being in CAD most of my career I like to make things fit very precisely.?ÿ I'm maybe not an OCD perfectionist, but need to know that what what I'm producing is "right" and that I would stand behind it (or admit an error) if questioned.?ÿ Not a problem with the design work I do, but real surveying still has me in a bit of a fog.?ÿ I need to know that I know and right right now I seem to be finding out more of what I don't.?ÿ I do a lot of construction surveying, but that relies many times on accurate and true boundary identification and rectification with what's on the ground.
So I'm not positive where to start, but two questions have arisen recently.
Using GPS or conventional, when you 'calibrate' the site the data collector does a (hopefully) slight rubbersheeting of the geometry based on the invariably slightly different measurements between control points or known monuments.?ÿ This produces a horizontal 'scale factor' and maximum residuals bot horiz and vert.
Even though they're unrelated technically, should that produced scale factor reasonably be close to what a combined scale factor is for the SPC datum at that location??ÿ If so, how close is close enough??ÿ How big would these residual discrepancies for horizontal and vertical be before you would discard or reshoot included points??ÿ For setting out perilously located footings on a 2 acre lot or setting a pool that adjoins a building limit how would I know that I know it's per plan if there's been some assumptions made based on transformation of the boundary geometry as it is on the ground vs plat??ÿ Would this be a bigger concern on a 100 acre lot??ÿ I know the answer is 'call in a licensed surveyor', but that's what I'd like to ultimately do and now as I study for it I see what needs to be addressed but not how.
Is the proper procedure to make 2 trips - first shooting all the corners located in a closed traverse, bringing that in and adjusting with software like starnet, TBC (by hand calc?) then taking that boundary info back out to shoot features??ÿ How far off can the raw horizontal distances shot be from the platted description before you apply a different approach??ÿ Would it be better for that work to use raw, as shot horizontal distances and internal angles at located corners to place features?
Second question that's arisen recently has to do with boundary location, which obviously I don't do but do want to be able to someday.?ÿ I saw a subdivision map recently that was created in 1978.?ÿ POB was described based on azimuth and distance from an NGS benchmark more than 5 miles away and the map was labeled as bearings based on "True North".?ÿ In 1978 I suppose that could be a baseline that was acquired by astronomic observation, but I suppose it could also be based on a magnetic bearing with declination applied.?ÿ How would you go about retracing this subdivision boundary??ÿ At 5 miles anything could easily create a huge variation in location.?ÿ Would you rely on "getting a good feeling" by shooting adjoining property boundary info??ÿ Could you presume he used NAD27 if it's not listed on the map or description??ÿ Basically, how would you retrace a single line and statement saying this is five miles from that in 1978??ÿ I'm sure a historic property search would be important but for this aspect (locating POB on that description) would you seek out field notes??ÿ Are they typically archived where the recorded land docs are (in our case I believe bureau of conveyances)??ÿ Let's say it's based on NAD27 and a magnetic declination; you go out and shoot the BM with GPS and stakeout the adjusted line to a POB 5 miles way, what if it's 5' from a found monument??ÿ What if there is no found monument?
Sorry for regurgitating this.?ÿ Maybe even resources you guys have trusted on these kinds of things would help.?ÿ I know working with an experienced surveyor would propably be the best way to go but I don't have that ability at the moment.
Mahalo.
One thing that you typed that I truly admire is "What I am worried about is not really knowing what the hell I'm doing...".?ÿ That's a problem, but you at least realize it is.
Your questions lead me to wondering what you will do with a license, if you pass the PS.?ÿ Will you be signing and sealing plans put in front of you without understanding what went into the calcs and adjustments?
It seems to me that your field experience and training is too lacking to be in the position of a PLS or RPLS.?ÿ You need to understand all of the things you question, being a great drafter in one thing, but, being the licensed person responsible for the data collection, appropriate adjustments, resolutions and the final drafting is quite different.
Please understand that I am not being negative or in any way trying to deter you.?ÿ You would benefit greatly bu working in the field for at least a few years, understanding what tolerances are acceptable, adjustments scaling and so much more.?ÿ Plenty of liability comes with that license.
That's my 2 pennies.?ÿ
Mahalo
Regarding scale factors. The scale factor resulting from a calibration of the site when using RTK is nothing more than a "best fit" of the observed to the record. It in no way is related to State Plane scale factors and should not be evaluated by comparing to State Plane scale factors. Do not stake a structure using scale factors. You are building a full size model not a scale model of the structure. You should use ground distances and a scale of 1.0000.
@chris-bouffard Thank you.?ÿ I do appreciate that.?ÿ And no, I wouldn't be stamping anything without knowing without any doubt what it is and the processes it took to get there.?ÿ If that ultimately means not being licensed in that, then so be it.?ÿ I'm just looking hard at it right now and need to decide if and how.?ÿ I do know a couple local surveyors that would (and have) employ me, but it'd be a huge change in almost everything to do it.?ÿ Doesn't mean it won't happen, though. Mahalo.
Bearings tied to a NAD27 monument and expressed in true north from 1978; at that time I would have occupied the monument, backsighted an AZ monument and traversed to the site 5 miles away.
It may have entailed a number of turns or one long distance meter shot to a nearby control point. Many NAD27 monuments are placed on good line of sight hills and you can often get a nice long sight from them. Then it's a matter of converting the SPC AZ to "true north" using the mapping angle. I do not think any magnetic bearings would be used since the surveyor was tied to SPC. A solar shot is also a possibility. I did them sometimes daily back then. But time was always iffy and within a couple of minutes of bearing was a decent result.?ÿ
I don't think the NAD27 monument should be considered as much of anything.
I would throw it out instantly (locate it sure, it's part of the description) and proceed from existing found monuments. Frankly, if you get within a foot to the NAD27 monument that would be amazing, but using that weak tie as a reference to establish a boundary,,,,,,,,,,,,,,that type of reference tie is the least call in a legal, down there with coordinates and lower than acreages. The monuments at the corners hold anyway. Find them!!!
Dave,
It sounds like you are about to make decicions that will take you from the technical to the professional track. Later in your career you will be able to point to the moment you turned, but for now it will be a series of choices. The fact you see the need to learn the evidence and legal side tells me you are starting the change now.
Eventually you will need the field and boundary experience and you should finish school. Many will insist you do those in a certain order, often exactly the same way they did. I say do it in the order it works for you. School is available fully on-line now. Finish it as soon as you can. The experience will mean big changes and you have to be prepared for that. The good news is, it is a great time to dive into fulltime land surveying. The money is good and firms want and need talent. Many outfits are helping employees with school costs and offering flex schedules so you can succeed. An honest person has a world of opportunity. If this doesn't describe your local narket consider moving.
The point of this ramble is that you know what you need. Go get it. Your CET and other experience give you a serious leg up on the competition. Push yourself now, before you get old and all the math leaks out.
Lastly, remember not to hold too tight to Brown. His works will get you through the exams, but many of the old absolutes have been corrected by the courts. Learn case citation structure and read appeals /supreme court decisions in your jurisdictions.?ÿ
Best of luck, Tom
@thebionicman Thanks, man.?ÿ Thinking about this the last couple days I decided I need a mentor.?ÿ It may be the right job opportunity, but many I see seem to be field and post processing data collectors, which I'm quite experienced at.?ÿ It may be connecting with a local surveyor and even paying for the opportunity to do the right work for them.?ÿ I like the finishing school thought as at least part of the solution.?ÿ Mahalo nui loa.
@dave-o?ÿ
Its a weird place to be, knowing that you know something but not nearly enough yet.?ÿ I'm in a similar space.
I was in the running for a party chief job in one the the biggest counties/cities in the country, and decided to back out because I don't need(or want I'm done showing new people how tough I am) 100% field work at this point, it's not going to help me move forward.
The fine tuning of the field knowledge within the legal research and boundary work is where I'm realizing my focus needs to be, and stay field savvy and sharp, just not 100% of the time.
Ping me anytime you want to comiserate.
