Kris Morgan, post: 455989, member: 29 wrote: First, it's not beginning with slop. Rounding off a hundreth or so of a foot is not what I would consider slop and I would encourage you not to accuse the subject surveyor of this when you are making independent calculations using centerline data and getting a number that is within 20 square feet over 3/4 of a mile. Second, if you use two different packages, you will get two SLIGHTLY different answers.
If you don't believe me, try this. Take the metes and bounds and pick a different corner to begin at. IT will give you a different answer. I was made to, and have made others when trying to teach precision, to take a traverse and compute it's closure. Then, once you do that, pick a different point of beginning and redo it. The difference in precision is amazing AND it's the same numbers you used to compute the first traverse with.
Obviously we can account for side lines that are not 90?ø when computing acreage, BUT you cannot do it with L*W, especially if you're worried over 20 square feet. Really, it's a strip of land, less than 1/8" wide, for the route length. I agree with wanting precision amazingly close, but it's important to keep an idea of the differences in number.
Your conundrum is exactly why I hate being forced to report quantities in square feet rather than acreage because I can use two different CAD packages with the same coordinate values and get different numbers and they're both correct.
I have no clue about your location, but as for Nevada, FYI:
Nevada Revised Statutes, 625.350,
3. If the land surveyed is described in terms of area, the record of the survey must show the area of the land surveyed in the following manner:
(a) In acres, calculated to the nearest one-hundredth of an acre, if the area is 2 acres or more; or
(b) In square feet, if the area is less than 2 acres.
I have not found this to be a particular issue in the past.
Thank you all for the replies, constructive or not. 🙂 I do want to mention that I know and respect the author of the descriptions, and his work is of excellent quality. It is not my intention to ??bag?? on him. I just feel that he has an old favorite ??go-to?? map-check program that is less than ideal in my own opinion. I hope no heads explode, when I mention that I have his CAD files as well? :smarty:
CV Nevada, post: 456031, member: 13195 wrote: I hope no heads explode, when I mention that I have his CAD files as well
And when you set your precisions to 5 or 6 decimal places and check the lengths of his lines are there numbers beyond the hundredths place value?
Here's the proper way to calculate area.
Sergeant Schultz, post: 456002, member: 315 wrote: You obviously don't work around here. 4 places is common, and I've seen 6 places on a large farm survey. Clueless, just frickin' clueless.....
Now that's funny, I don't care who you are:)
Rule of thumb, you go to acreage after a certain sq.ft. (43560). Acre area should be expressed in hundredths of acres. 20 sq.ft. is not much, length of line x width equals area. It doesn't matter if your center line extends to a perpendicular line. As long as the intersecting line doesn't turn before the row crosses.
CV Nevada, post: 456031, member: 13195 wrote: Thank you all for the replies, constructive or not. 🙂 I do want to mention that I know and respect the author of the descriptions, and his work is of excellent quality. It is not my intention to ??bag?? on him. I just feel that he has an old favorite ??go-to?? map-check program that is less than ideal in my own opinion. I hope no heads explode, when I mention that I have his CAD files as well? :smarty:
Just because some of the replies did not validate what you think you know about calculating areas doesn't mean they weren't constructive.
Kris gave you the most detailed explanation and the best answer of what you need to understand about your job in this part of QA/QC.
If you don't understand the limits of the measuring tools and methods, then you won't understand the value, which is not simply a number representing a magnitude, but a confidence, or +/- component.
If you don't understand the confidence limits of the reported measurements, or the effect of reporting precision of the measurements, then you won't understand the potential magnitudes of reasonable and expected rounding errors in the calculations made from the measurement data.
The problem you posted and your rejection of sound advice shows that you only go back one step in that lineage of understanding measurement data basics to demonstrate your lack of knowledge. We don't even need to go as far as the actual accuracy of field measurements. This is purely a matter of significant figures and rounding. If you start telling people in your own organization that the surveyor has given you slop to review, and especially if you convey that attitude to the surveyor, it won't take much for him, or anyone else who actually understands math, that you are coming from a place of incompetence.
Since you don't think Kris' advice was constructive, you probably think I'm simply flaming you. Actually, this is given as friendly advice when I strongly urge you to review a good math or science text which dedicates at least a couple pages to a discussion of significant figures before you discuss your concern about these supposed discrepancies with anyone you work with. This is a very easy point of incompetence to correct. You would be doing yourself a big favor by re-reading Kris' posts, reading up on sig figs, and doing a little application experimentation all toward the goal of self education before you really embarrass yourself by demonstrating your lack of knowledge in this regard.
Warren Smith, post: 456039, member: 9900 wrote: Here's the proper way to calculate area.
It's been at least 20 years since I've calculated area longhand by DMD. Although that and so many other things we do seem incredibly tedious when compared to doing them with the tools at our disposal now, I'm thankful that I entered the profession when much of the work had to be done longhand as to calcs and drafting and often in the field with equipment that was the same or very similar to that commonly used by surveyors several decades before I began. I believe it's given me a better perspective for what reasonable discrepancies within past surveys should be and for what reasonable results should look like now, as well as the limitations of measured and calculated data, modern and historic.
When someone gets too wrapped up in the reporting or precision of calculations, it can be easy to forget the basic principles of math and of measurement science.
Here is a link to an excellent text that should be read by all surveyors and anyone who commonly deals with measurement data: https://www.amazon.com/Practical-Measurement-Science-Engineering-Technology/dp/0471031569/ref=sr_1_9?s=books&ie=UTF8&qid=1510876991&sr=1-9&keywords=barry+measurements
Some of you guys are trying to make a mountain out of a molehill regarding area. I did a lot of route surveys when I was in business and calc'd a lot of areas for the right of way. The survey lines were measured using horizontal distances and actually shown on the survey drawing to the nearest 0.10' and bearings to the nearest minute. The actual facility length was based on slope for pipe, cable or whatever for constuction. That's also how the contractor was paid, pioe length, not horizontal measurement. On buried cable routes, we aslo did what was called trench details which were slope chained so they could design their cable and appurtenances to fit the ground length. The map listed for each ownership, footage, roddage, and acreage based on the survey line length and the width of the right of way. Doing a route survey on grid B.S. is bad practice.
I made up a little drawing showing area calc's by inversing around the perimeter of the right of way and by just taking the center line length times the right of way width and there is not enough variation in the square footies to worry about. I've attached it for reference.
Granted, there may be an instance where it would be necessary to do a perimeter run out, but only on rare occasions. Acerage should only be shown to the closest foot anyway.
Cameron Watson PLS, post: 456035, member: 11407 wrote: And when you set your precisions to 5 or 6 decimal places and check the lengths of his lines are there numbers beyond the hundredths place value?
I donnno, I don't do this, do you?
eapls2708, post: 456049, member: 589 wrote: Just because some of the replies did not validate what you think you know about calculating areas doesn't mean they weren't constructive.
Kris gave you the most detailed explanation and the best answer of what you need to understand about your job in this part of QA/QC.
If you don't understand the limits of the measuring tools and methods, then you won't understand the value, which is not simply a number representing a magnitude, but a confidence, or +/- component.
If you don't understand the confidence limits of the reported measurements, or the effect of reporting precision of the measurements, then you won't understand the potential magnitudes of reasonable and expected rounding errors in the calculations made from the measurement data.
The problem you posted and your rejection of sound advice shows that you only go back one step in that lineage of understanding measurement data basics to demonstrate your lack of knowledge. We don't even need to go as far as the actual accuracy of field measurements. This is purely a matter of significant figures and rounding. If you start telling people in your own organization that the surveyor has given you slop to review, and especially if you convey that attitude to the surveyor, it won't take much for him, or anyone else who actually understands math, that you are coming from a place of incompetence.
Since you don't think Kris' advice was constructive, you probably think I'm simply flaming you. Actually, this is given as friendly advice when I strongly urge you to review a good math or science text which dedicates at least a couple pages to a discussion of significant figures before you discuss your concern about these supposed discrepancies with anyone you work with. This is a very easy point of incompetence to correct. You would be doing yourself a big favor by re-reading Kris' posts, reading up on sig figs, and doing a little application experimentation all toward the goal of self education before you really embarrass yourself by demonstrating your lack of knowledge in this regard.
Flame on, you aren't talking to a spring chicken! I could glean from a lot of the comments here, that some could not create their own strip easement, and calculate the area with any confidence? That's how silly some of the reply's have been...(snarc off)!
You may not be a spring chicken, but if you don't understand something as basic as significant figures, and this thread demonstrates that lack of understanding quite clearly, you have no business checking anyone else's work. Perhaps it would be best in the long run for the profession and for any affected by projects you may work on in the future if you do showcase your incompetence by raising this as an issue.
Maybe the surveyor who you are suggesting is giving you crap to work with will make a call to NVBELS. You might listen to advice in a conversation about competence from them.
I've been surveying for about 37 years. I've learned a lot along the way. I continue to learn from my colleagues in forums like this and in other settings on a regular basis. On occasion, I've learned that what I thought was the right way to do something isn't right at all. I'm no spring chicken either, but if I get to the point where I can't learn something, whether it's a new concept or correction to some part of my existing knowledge base, then it's time for me to hang it up.
If I ever ignore several LSs who have the reputation for knowing what they're talking about when they tell me to pull my head out of my... technology, I hope to have a friend good enough to talk to me about considering retirement.
You've been told by several, now the choice is yours: pull your head out, or go make a fool of yourself. Makes no difference to me which you do as long as I don't have to work with you.
eapls2708, post: 456049, member: 589 wrote: Just because some of the replies did not validate what you think you know about calculating areas doesn't mean they weren't constructive.
Kris gave you the most detailed explanation and the best answer of what you need to understand about your job in this part of QA/QC.
If you don't understand the limits of the measuring tools and methods, then you won't understand the value, which is not simply a number representing a magnitude, but a confidence, or +/- component.
If you don't understand the confidence limits of the reported measurements, or the effect of reporting precision of the measurements, then you won't understand the potential magnitudes of reasonable and expected rounding errors in the calculations made from the measurement data.
The problem you posted and your rejection of sound advice shows that you only go back one step in that lineage of understanding measurement data basics to demonstrate your lack of knowledge. We don't even need to go as far as the actual accuracy of field measurements. This is purely a matter of significant figures and rounding. If you start telling people in your own organization that the surveyor has given you slop to review, and especially if you convey that attitude to the surveyor, it won't take much for him, or anyone else who actually understands math, that you are coming from a place of incompetence.
Since you don't think Kris' advice was constructive, you probably think I'm simply flaming you. Actually, this is given as friendly advice when I strongly urge you to review a good math or science text which dedicates at least a couple pages to a discussion of significant figures before you discuss your concern about these supposed discrepancies with anyone you work with. This is a very easy point of incompetence to correct. You would be doing yourself a big favor by re-reading Kris' posts, reading up on sig figs, and doing a little application experimentation all toward the goal of self education before you really embarrass yourself by demonstrating your lack of knowledge in this regard.
Obviously you haven't been reading this thread very thoroughly! I haven't discussed measurements at all! I am speaking to given values, and apparently some here do not believe that given identical values, any two surveyors can arrive at the same calculated area.
eapls2708, post: 456068, member: 589 wrote: You may not be a spring chicken, but if you don't understand something as basic as significant figures, and this thread demonstrates that lack of understanding quite clearly, you have no business checking anyone else's work. Perhaps it would be best in the long run for the profession and for any affected by projects you may work on in the future if you do showcase your incompetence by raising this as an issue.
Maybe the surveyor who you are suggesting is giving you crap to work with will make a call to NVBELS. You might listen to advice in a conversation about competence from them.
I've been surveying for about 37 years. I've learned a lot along the way. I continue to learn from my colleagues in forums like this and in other settings on a regular basis. On occasion, I've learned that what I thought was the right way to do something isn't right at all. I'm no spring chicken either, but if I get to the point where I can't learn something, whether it's a new concept or correction to some part of my existing knowledge base, then it's time for me to hang it up.
If I ever ignore several LSs who have the reputation for knowing what they're talking about when they tell me to pull my head out of my... technology, I hope to have a friend good enough to talk to me about considering retirement.
You've been told by several, now the choice is yours: pull your head out, or go make a fool of yourself. Makes no difference to me which you do as long as I don't have to work with you.
You are a fool Evan! Go beat on your little chest if it makes you feel like a big surveyor!
eapls2708, post: 456068, member: 589 wrote: You may not be a spring chicken, but if you don't understand something as basic as significant figures, and this thread demonstrates that lack of understanding quite clearly, you have no business checking anyone else's work. Perhaps it would be best in the long run for the profession and for any affected by projects you may work on in the future if you do showcase your incompetence by raising this as an issue.
Maybe the surveyor who you are suggesting is giving you crap to work with will make a call to NVBELS. You might listen to advice in a conversation about competence from them.
I've been surveying for about 37 years. I've learned a lot along the way. I continue to learn from my colleagues in forums like this and in other settings on a regular basis. On occasion, I've learned that what I thought was the right way to do something isn't right at all. I'm no spring chicken either, but if I get to the point where I can't learn something, whether it's a new concept or correction to some part of my existing knowledge base, then it's time for me to hang it up.
If I ever ignore several LSs who have the reputation for knowing what they're talking about when they tell me to pull my head out of my... technology, I hope to have a friend good enough to talk to me about considering retirement.
You've been told by several, now the choice is yours: pull your head out, or go make a fool of yourself. Makes no difference to me which you do as long as I don't have to work with you.
I recommend some reading lessons for you.
Kinda sounds like we're back in Singapore.
Nevada,
The differences you are describing can be attibuted to any number of things. It could be as simple as one person running an inverse check, another running a mapcheck, maybe using a bpoly area or just simple rounding. Regardless of the reason they are insignificant. And like it or not, those dimensions relate to measured lines. The returns of the next Surveyor will either be different by more than the amounts you describe or mildly fictitious. I would be more concerned that the easements can be placed in a single definite location than half hundredths of rounding.
CV Nevada, post: 456073, member: 13195 wrote: You are a fool Evan! Go beat on your little chest if it makes you feel like a big surveyor!
I recommend some reading lessons for you.
Don't know you, but I do know Evan. You owe him an apology. You will not get much help if you come on here and abuse a well respected, thoughtful member that has been a great contributor over many, many years.
Kris Morgan, post: 455989, member: 29 wrote: First, it's not beginning with slop. Rounding off a hundreth or so of a foot is not what I would consider slop and I would encourage you not to accuse the subject surveyor of this when you are making independent calculations using centerline data and getting a number that is within 20 square feet over 3/4 of a mile. Second, if you use two different packages, you will get two SLIGHTLY different answers.
If you don't believe me, try this. Take the metes and bounds and pick a different corner to begin at. IT will give you a different answer. I was made to, and have made others when trying to teach precision, to take a traverse and compute it's closure. Then, once you do that, pick a different point of beginning and redo it. The difference in precision is amazing AND it's the same numbers you used to compute the first traverse with.
Obviously we can account for side lines that are not 90?ø when computing acreage, BUT you cannot do it with L*W, especially if you're worried over 20 square feet. Really, it's a strip of land, less than 1/8" wide, for the route length. I agree with wanting precision amazingly close, but it's important to keep an idea of the differences in number.
Your conundrum is exactly why I hate being forced to report quantities in square feet rather than acreage because I can use two different CAD packages with the same coordinate values and get different numbers and they're both correct.
Area is only an estimate unless your taking the variations of the topography into account. If there's a Mountian in the middle of your project you have more area. L x W is just an approximation at a set elevation. Area means squat to everyone but the tax man because that's what he uses to calculate your taxes with.
We all knew Kent would reappear sooner or later.
Holy Cow, post: 456122, member: 50 wrote: We all knew Kent would reappear sooner or later.
Maybe I'm TDD?:p LOL!
