Hi all,
I've gone through the very useful Caltrans material here, http://www.dot.ca.gov/landsurveys/workbook.html and have a question about a specific question in the PLSS section.?ÿ Can someone explain the reasoning of this question to me??ÿ I can't neatly include the content of the question here since it is rather involved and multi-part.?ÿ You'll have to look at the PDF.?ÿ
It is question I on page 21 of this PDF, http://www.dot.ca.gov/landsurveys/docs/lsit-workbook/12.pdf pertaining to determining the east 1/4 corner (of section 6) from a witness corner (that is on line).?ÿ I sort of liked answer 3 which is the "single proportion along the line" answer.?ÿ On page 25, the answer is listed as 4, "none of the above."?ÿ That also rejects answer 1 which is the "record measurement back from the WC" answer for if it were a specific measurement more like a bearing tree than something on line. ?ÿ An answer which is not included in the "record measurement of 40 ch from the SE section corner" answer.?ÿ What is the correct approach to this question??ÿ When using that approach, what coordinates do you get?
Best regards, Eli
The only reason I can think of is a WC is not necessarily on-line so there is insufficient information given to calculate the coordinate of the quarter section corner. Therefore under this reasoning none of the above is correct.
The 1973 Manual indicates that proportioning would be correct if the WC is on-line but it adds that each case is different, see the notes.
A point on line is called a WP (witness point).
I'd be cautious about blindly accepting an answer to a question that appears to have been on the 1988 LS exam.?ÿ There are differences between the 1973 Manual and 2009 Manual.?ÿ I suggest you look at Secs. 6-23 "Witness Corners" and 7-35 "Section Boundaries" in the 2009 Manual as guidance.
For this problem:
1) is 1.07 ch. south of the witness corner on a line between the witness corner and the SE Cor. of Sec. 6
2) is to mistakenly accept the witness corner as now monumenting the E1/4 Cor.
3) is 1.08 ch. south of the witness corner on a line between the witness corner and the SE Cor. of Sec. 6
4) is something else.
If you determine that the proper proportionate method is to single proportion between the witness corner and the SE Cor. of Sec. 6 then the record dimension between the two is 41.09 ch. and the measured is 41.454 ch., which would place the E1/4 Cor. 1.10 ch from the WC.
Or should you single proportion between the WC and the CC corner in which the record is 33.60 ch. and the measured is 33.055 ch., which would place the E1/4 Cor. 1.072 ch. from the WC??ÿ Then all you need to decide is whether the E1/4 Cor. should be on the extension of the line between the CC and WC or on the line between the WC and the SE Cor. of Sec. 6.
ETA:?ÿ One last question:?ÿ Should the measured distance be from the WC to the CC or from the WC to the line between the two standard corners on the township line??ÿ If so, don't forget it's curved!?ÿ ?????ÿ
It's an interior corner so should be a double proportion.?ÿ Points 11 and 8, and point 7 and ....... nothing to go with it.?ÿ Go back to the field and find more evidence.
The correct way to do this is the same in both manuals.
Where are you getting the 41.09?
You cant single proportion between two points on the same side of the corner you are trying to reestablish.
The distance between the WC and the township line cant be measured, there is nothing to measure to, that would be a calculated distance.
One has to assume that all these measured coordinates were measured geodeticaly, so the curvature, is already accounted for.
I assume you are joking, but that could be confusing for someone asking for help.
This test in unfortunate in that it encourages the kind of assumptions that get surveyors into trouble every day. You have to assume that the original survey was done by the standard method and was reported to be perfectly cardinal. Never attempt something like this without the original plat and the original notes.
The Manual's primary methods to replace lost corners are only applicable when the prescribed methods were followed. They often weren't. The manual allows deviations due to particular circumstances and by the Chief Cadastral Surveyor's directions, not to mention all the short cuts taken by the contract surveyors.?ÿ
I recently had a discussion with a surveyor who presented good evidence that the e-w 1/4s were stubbed out, but then he used double proportion to reset a lost section corner.?ÿ The Manual is not an excuse to not use your critical thinking skills.?ÿ
Where are you getting the 41.09?
My mistake. It's my old weak eyes.
The distance between the WC and the township line cant be measured, there is nothing to measure to, that would be a calculated distance.
The two standard corners were found and shot in (labeled 1 and 4) so one can measure to the township line if one believes that is the correct way to handle a closing corner situation.
Right, but in the language of the test, the true closing position would not be a "measured" distance. A big part of answering these questions is understanding the test.
Whether that is the right way to handle the CC depends on what is in the notes of the latest official survey, and any other intervening surveys.
The Manual is not an excuse to not use your critical thinking skills.
The 2009 Manual often states that another method should be selected if the default method gives an unsatisfactory result. Since I work almost exclusively with mineral survey resurveys I'm fond of the Manual adopting Meldrum's advice of:
There is no hard and fast rule for reestablishing lost corners of lode mining claims. The method should be selected that will give the best results.
Thanks to everyone for looking at this and especially to everyone who replied.?ÿ
@dave-karoly thanks for pointing out that WC/WP distinction.?ÿ I was perhaps too believing of the diagram and of the record measurements. ?ÿ I failed to point this out in my initial post, but I'm using the 2009 manual even though this question would have been worked with the 1973 manual.?ÿ Re-reading from the 2009 manual 4-16, 4-18, 6-27, 6-29, and 7-35 (thanks for this one @gene-kooper) suggests a fair amount of possible variation with WC and WP and points to the notes.?ÿ
@dave-karoly and @aliquot and sections of the manual all point to the notes.?ÿ That's true and can always be the answer, "read the plat and notes and evaluate the recovered evidence to see what actually happened and follow accordingly."?ÿ I don't mind the contrived test examples since having a good understanding of the standard method is needed for when to vary from that.?ÿ Learning some common unofficial methods like stubbing out e-w 1/4s is helpful too since it is another search area and another way to reason with the recovered evidence.?ÿ In some areas the three mile method is a good one to know too.?ÿ
?ÿ
I'd be cautious about blindly accepting an answer to a question that appears to have been on the 1988 LS exam.?ÿ There are differences between the 1973 Manual and 2009 Manual.?ÿ I suggest you look at Secs. 6-23 "Witness Corners" and 7-35 "Section Boundaries" in the 2009 Manual as guidance.
For this problem:
1) is 1.07 ch. south of the witness corner on a line between the witness corner and the SE Cor. of Sec. 6
2) is to mistakenly accept the witness corner as now monumenting the E1/4 Cor.
3) is 1.08 ch. south of the witness corner on a line between the witness corner and the SE Cor. of Sec. 6
4) is something else.
If you determine that the proper proportionate method is to single proportion between the witness corner and the SE Cor. of Sec. 6 then the record dimension between the two is 41.09 ch. and the measured is 41.454 ch., which would place the E1/4 Cor. 1.10 ch from the WC.
?ÿ
That is a good way to summarize and present the answers.?ÿ Can you look at answer 3 again??ÿ I think that record is 41.07 ch not 41.09 which I think would revise answer 3 to :
3) is 1.08 ch. south of the witness corner on a line between the witness corner and the SE Cor. of Sec. 6 at single proportionate measure.?ÿ
The correct way to do this is the same in both manuals.
Can you be more specific as to what is the correct approach to this question (going along with the contrived standard method assumptions of the question)?
6-7 (2009): "For corners reestablished by single proportionate measurement, the true point for the corner will be determined by single proportionate measurement between the witness corner and the opposite controlling corner."
Yeah, tests like this certainly have their place, the problem is when the instruction that goes with them doesn't emphasis that the "standard methods" should only be used if the standard assumptions are shown to be true. If I was writing a test like this I would include a statement that said something like, "your research and field measurements show that the survey you are resurveying was preformed in the standard manor as prescribed by the XXXX manual" I would also include a question where that statement was not provided. The correct answer would be, "ït can not be determined from the provided information."
Training students (or apprentices ) to make assumptions by default is not a good idea.
7-35 is not applicable here, because the 1/4 cor. is not lost.
I'm just as confused as you are...I'm just guessing my explanation above is the reason McCavitt selected D.
It's a bad question, in my opinion.
No, just wasn't paying attention. Note to self: no test questions before coffee.
6-27 (2009). Does that math work out to answer 3 (I think it does but I'm checking here)? If so, while I like that answer and it is how I approached the problem with the given information supplemented with some assumptions based on what was missing, it is not the answer given in the answer key. Which has me leaning towards @dave-karoly explanation of the intention of the question and answer which is that a WC is not necessarily on line and that not enough information is provided in the question. If this WC is not on line, then the 1/4 corner would be recovered using bearing and distance from the notes.
Having read again, I don't see why correct answer is not #1.?ÿ In the case of a witness corner there was no monument set at the corner because it couldn't be for some reason.?ÿ So its never been anything but 40, why change it now? When it state all found corners are accepted, that means to me we accept WC as online. Whatever measurement error there is should be place in the fractional part. Shouldn't be any proportion along this line in my view.?ÿ
You must PRORATE LOL
