Went to the local baseline (Hillsboro, OR). A highway sign had been erected smack in the middle of it, making it impossible to use. Started making calls to the County Surveyor and DOT survey department.?ÿ The sign had been there more than 6 months, no one had reported it. DOT policy was to visit baseline before every new project or every 6 weeks, whichever was less.?ÿ
Went to baseline near Tulsa, OK. Completely overgrown. Some of the trees on line were 6" in diameter.?ÿ?ÿ
We certainly are capable of making more precise measurements than that, but really who cares? We could spend more time measuring and more money on equipment, but it won't make any difference to our clients, their neighbors, the public, judges, or anyone else.?ÿ
I dont see a reason to either drive up your clients cost, or reduce your profit for the sake of precision that only a geomatics?ÿ engineer would care about. What is important is developing procedures that catch and eliminate blunders.
Edit:?ÿ of course if your practice includes high precision engineering or geophysical measuring then the above doest apply.?ÿ
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What is important is developing procedures that catch and eliminate blunders.
Very much agree. Unfortunately there is a not-insignificant number of surveyors who (a) have no procedures in place, (b) do not understand error analysis and blunder trapping, nor the capabilities of the technology they use, and (c) could care less about it.
Then they slap a generic statement about how their work conforms to statutes concerning traverse closure or relative positional precision, without ever even performing any analysis of their work. The only way to find out what they really did is to call them.
Years ago I didn't really understand why we had to provide adjustment reports, raw data and reduction narratives as deliverables to certain public entity clients, but gradually figured out the above. While those surveyors may never win big-ticket work they sure can wreak havoc in the public record.
"We have become very good at measuring our mistakes more accurately."?ÿ?ÿ
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I get the argument that the sky won't fall over two tenths, but we differ after that.
There is no reason not to do better with any remotely modern equipment and sound procedure. We aren't talking about wrapping 16 angles and chaining four times. If you are doing basic error detection you will catch 0.2' in a half mile. You almost have to work harder to slop it up that much.
The big issue is no original or at least quasi-original monuments set by the platting surveyor. To resurvey section lines remote to the lots each time a new lot is monumented is inviting error larger than necessary.
Set the corners for the subdivision before any lots sell, that is the key. Waiting until the infrastructure is installed is rational, but leaving lots unmonumented until a sale is not good practice, now you have whoever is hired doing what amounts to the first survey.
0.14' along a far away section line becomes 0.2' at the lot corner, who saw that coming??ÿ
These lots should be surveyed together at least once and it should be the surveyor who signed the plat.?ÿ
Imagine, you buy a lot in a Subdivision, there are no monumented corners, only paper ones. I won't do that.?ÿ?ÿ
Having them in the CBL list is one thing...actually being able to use them is another...any that are on an airport have become much more difficult to use.
@rover83?ÿ ?ÿ"Blunder Trapping"?ÿ Now that's a good phrase I can use to explain those meaningless measurements I make that have nothing to do the actual survey.?ÿ Thanks.
But why worry when you don't match the last surveyor by 0.2' in 1/2 mile. Are you going to reject their monuments, or tell your client that there is a problem?
I completely agree. However, lets assume the person that "missed" by 0.2' ran a loop, and that the point set was, in fact, occupied as part of that traverse.
When they got around the block and missed closure by 0.2', then what?
The fact that a surveyor should know the precision and accuracy of their work should be agreed upon by all of us. What I think we see here is that some surveyors acknowledge that under certain circumstances 0.2' (or more) could be acceptable.
Reminds me of some years back a crew ran a traverse through a property for a topographic survey. We missed closure by about 0.15' horizontal. For design topo of a plat, that is good enough to walk away from. BUT, I know we should NEVER have a traverse that far out given the conditions. I worked it through StarNet back and forth (they did have some cross ties) and found a specific occupation point that seemed to be the culprit. Turns out that there were equipment/procedure issues due to some new equipment. Sure we could have "let it ride", but it was worthwhile finding out what was going on.
One issue is one surveyor reporting in grid while everyone else is reporting on ground.?ÿ Can get 0.2 in a half mile in places.
0.2 ft. per ?« mile?
Hell, out here in the Mountain West, it can EXCEED 1.5 ft. per ?« mile! Even more if someone is using UTM (or playing around in some parts of Montana with the single zone Montana SPC).
Loyal
@loyal -had a surveyor testify in a condemnation suit that the state was trying to cheat his client out of land because the were using grid measurements buying a strip 20 ft wide across the front of a section... our compensation offer was to the hundredth hog an acre ... rounded up....:eyeroll
Where I work I??m just happy to find that they actually set a rebar. I??ll live with the 0.2?? difference. At least we are talking about the same piece of property.
