> So..what is the issue? Did the original plat state it was on true north? Are you required to have your surveys based on a recoverable bearing basis?
Yes, Texas practice requires some statement as to the basis of bearings and that they refer to something other than the sparkle of sunlight on a pond. In the 19th century, the bearing basis of a survey run in that area would have differed by about 1 degree counterclockwise from true. One value of variation that was used for years was wrong by about that amount. So, it's striking that in the modern era when GPS is widely used and solar observations are a snap to reduce, that bearings would be so far from any independently reproducible value and in greater error in an absolute sense than most of the 19th century surveyors reported.
Bearing Basis for Profit
Can somebody explain to me how "east line of parcel is assumed north" tells me anything? What's special about that line? It looks to me like it's equivalent to "user can pick any line on the plat and use its bearing for computation."
Is there something about error propagation I'm missing? I doubt it, since the basis of bearing statement gets used most often on transit/total station jobs where what is actually measured is angles.
> So you think your client only wants the plat to buy the house, and once he buys it, he no longer cares where his property line is?
I never said that.
It seems as if the surveyor that Kent was re-tracing did a decent job - just that his bearings didn't match what Kent calc'ed. Who cares?
As long as there are monuments, and the relationships between the lines and monuments agree, doesn't matter whether the bearing is S46°11'34"E or S86-00-00E. I'm not just going to hold or stake out a bearing on that alone. And any landowner who's out marking his own PL based on a bearing on a plan is surveying without a license.
I didn't take it that the monuments were staked incorrectly - just that Kent's calc'ed bearing didn't match the plan bearing, supposedly on the same system.
> Come on guys. concerned about 2 minutes of angle in 700 foot line? Hit the corner with a lawn mower and it would be out that much.
If a lawn mower knocks out a corner a half of a foot, then we need to reset that corner maybe. However, someone should be setting all of their own original corners to better precision than that. Even 20 years ago we would be using a theodolite an doubling angles. You would never see one of our own monuments out more than a few hundredths relative to the next adjacent monument.
I don't have an issue with someone assuming a bearing based on an older map, and showing all their angles, etc. However, I would expect to match their own monuments to a higher-order of precision (relative precision to their own monuments). RTK is slop. If you can do your work to a higher order than 0.4' and prove it with RTK then it is fine, but that wasn't done here it would appear.
I refuse to do this kind of sloppy work on my watch. I may have to live with others having to do that, but I can certainly complain about it.
(So as not to misunderstand, I deal with not matching between found monuments by a half-foot and more all the time. Generally they are monuments set by different people, or from different origins, or who knows what-all including busts.)
> Come on guys. concerned about 2 minutes of angle in 700 foot line? Hit the corner with a lawn mower and it would be out that much. How about describing the lot based strictly on angles and just show a north arrow on the plot?
Well, one of the purposes of my survey was to describe the actual shape and location of the lot in a way that it could be put back on the ground more or less exactly after construction is finished and at any time in the future using my map. The front of the lot was about 125 ft. and the sidelines about 352 ft., so I thought setting some spike and washer reference markers in drill holes in the concrete curb on the prolongations of the sidelines and determining the actual bearings of lines would accomplish that best.
> I didn't take it that the monuments were staked incorrectly - just that Kent's calc'ed bearing didn't match the plan bearing, supposedly on the same system.
Yeah, the boundary markers are where they are. It looks to me as if the front and rear lines of a series of lots were independently staked and probably with RTK in the mix somewhere, I'd guess.
Bearing Basis for Profit
> Can somebody explain to me how "east line of parcel is assumed north" tells me anything? What's special about that line? It looks to me like it's equivalent to "user can pick any line on the plat and use its bearing for computation."
>
> Is there something about error propagation I'm missing? I doubt it, since the basis of bearing statement gets used most often on transit/total station jobs where what is actually measured is angles.
It might only help for orientation. You have to face the map in the right direction. Get on that line and assume "North" to find the other corners, and reset the marks. The relative bearings will tell you how well your hitting.
It doesn't "tell" you as much as a better bearing-base and bearing-base statement would, but it does tell you what you can expect, and how/why the numbers are what they are on the plat.
> As long as there are monuments and the PL/survey can be retraced by the information on the plat, I'm good.
But stuff happens and when the monuments are disturbed or destroyed, things fall apart. Having an independently reproducible bearing basis adds one more important piece of information that stabilizes boundaries.
just keeping you honest
Kent, they are probably just using an assumed bearing base so that you aren't tempted to take shortcuts by grabbing a single monument and start blazing the line.
It has always been very common in Nebraska to use an assumed bearing of "NORTH" along the north-south line of a parcel even if it was skewed. For instance, if you were surveying the NW 1/4 of a section, the west line of that quarter would be N 00°00'00" E (Assumed Bearing). Then the north line along the north side of that quarter might be N 89°56'17" E based upon the measured interior angle of 90°03'43". The plat and legal description state "Assumed Bearing" after that first course.
If someone later comes up with a true bearing of N 01°23'12" W along the west line based upon GPS, then they should know that the north line should then be close to N 88°33'05" E based upon the 90°03'43" angle from the previous surveyor if they want to match.
We are required to list record distances, but not record bearings on the plat. Most new parcels on plats are built from angles and distances and not record bearings. The GIS folks have had lots of trouble with this and new parcels sometimes get put in next to existing ones based upon two different bearings basis that causes overlaps or gaps.
A land owner who uses his property, which might include modifications such as building a fence, planting a garden, or cutting down a tree, based on a plat, is using the plat he paid for, not land surveying. If he puts something in the ground that meets the state's definition of an adequate land survey monument, he might be surveying without a license, depending on the laws of the state. How he uses the plat is up to him, but if he does it wrong, he is liable to the adjoinder for damages. Estimating the line with a compass if the monuments are not intervisible might be good enough, depending on just how close that tree he wants to cut down is to the line. Of course, the landowner would be well-advised to check his understanding of compass use on a pair of monuments that are intervisible, since in the general case, bearings on plats prepared by US surveyors have no relationship to the axis of rotation of the earth or the magnetic field of the earth, as is demonstrated by this thread.
Every survey I come across are based upon metes and/or bounds descriptions.
Many of the older descriptions appear to have been based on the assumption that all fences and roadways are North, East, South or West and all other boundaries were calculated.
In more recent times, it is either at the lawyer's office or the title company, the basis of bearing statements are edited out when the information is placed in the deed.
To try and force the deed makers to include the basis of bearing into the deed I have put the information in the text of my descriptions and also inserted the date of the actual survey and the fact that I surveyed the property.
On occasion, the basis of bearing and the date of survey and my name are all edited from the text that is inserted into the deed.
My opinion is that they insert my actual signed and sealed and delivered papers into the deed as exhibit(s).
😉
> Most new parcels on plats are built from angles and distances and not record bearings. The GIS folks have had lots of trouble with this and new parcels sometimes get put in next to existing ones based upon two different bearings basis that causes overlaps or gaps.
That seems very strange to me considering that when land is subdivided, the small additional cost of determining some independently reproducible bearing basis is spread over as many lots as are in the subdivision.
Nebraska and Oklahoma seem similar in nature according to J.P.
As crazy as it may seem to Kent, in the past surveyors called the closest N-S section line to their survey "North" and ran with it. Basically it reduces the act of following a survey's bearings down to "transit angles", or positional relationship.
I had a crew chief for a few years that was licensed in Texas. It was hard for him to get his head around the fact we were so flippant about our bearing base... and the rectangular system gave him fits. He was a good surveyor and originally wanted to get licensed in Oklahoma...he decided not to..I don't blame him.
Work picked back up south of the river and the young man got back where he was comfortable.
Since Texas does not provide for recording plats, I think it's interesting what Texas land owners do with their plats once the transaction or construction project that instigated the survey is complete. I wonder if they are like the purchasers of consumer products, who throw all the user manuals away with the packaging, and then wonder why not even their 16-year-old family geek can't figure out how to set up their new electronics. (Granted, this is less of a problem now that most product manuals are available on the web.)
> As crazy as it may seem to Kent, in the past surveyors called the closest N-S section line to their survey "North" and ran with it. Basically it reduces the act of following a survey's bearings down to "transit angles", or positional relationship.
That probably sort of worked as long as the same 60d nails supposed to be the section corners were in place in the county road pavements. :>
End all the anguish, file all Boundary Surveys in the Public Record, review those records with their narrative, Narrative's should be required. The what and why should be reveled along with what evidence was used, what and why some evidence found was rejected and what the Bearing Base was and it's character. The Bearing Base's can be assumed, based on the magnetic line between the center of the foundation of the Statue of Liberty and the Northwest corner of Fisherman's Wharf in San Francisco in 1926 or on a solar observation does not really matter as long as it can be repeated and in recording state there are numerous ways to get back to the record bearings. Filing Boundary surveys in the Public Record will solve many problems such as this, might take a few years after that requirement is in place to build up a data base, but those filed records would soon become useful tools, as many have discovered. Have few overlapping problems in recording states, rotating several surveys to match one for compilations is common. Want to work in true, that's fine but don't expect a State Grid to remain a stable reference over time, we live on a moving surface and because of that, local physical evidence, be it monuments or a local grid based on local monuments will always be King. Without that local base, bearings might as well be assumed anyway.
jud
Kent I can somewhat understand what you are saying, but realize that in the PLSS most parcels are based upon section lines oriented in a closely north-south or east-west direction. Even if the parcel is an irregular metes and bounds tract in the center of the section, you can still figure out where you need to be. For the most part, things have always been recorded here, so you already have a map in hand before headed to the field. I think many of us can only grasp a situation from our own experience and the methods being used by someone from another part of the country can often seem so very strange.
> I can somewhat understand what you are saying, but realize that in the PLSS most parcels are based upon section lines oriented in a closely north-south or east-west direction.
Well, my observation was just that defining a tract in relation to a section line (as using the section line for a bearing basis would) works for exactly as long as the section line is monumented in the same position. Evidently in some localities multiple choice section corners are not uncommon, so I'd think you'd end up with multiple choice bearing basis, a situation that would have been perfectly avoidable had some independently reproducible bearing basis been used.
I think I understand that the practice of simply assuming that the section line runs North is for the convenience of abstractors and tax assessors. Over the long haul, it doesn't seem to foster permanence and certainty of boundaries in a way that actually knowing the directions of parcel lines would.
