Aloha,
I've never done resection before. I want to establish the line for clearing from pt110 to pt111
There are no other point in line of sight to setup station and do backsight. I only show few large threes but it is over grown a long the line and everywhere. The large tree close to pt111 is a huge Ficus tree with tons of aerial roots. I could traverse over here about a thousand feet away again with a lot of setup and breakdown due to obstacles. So I thought it is good time to learn resection. I read about it and decide I should have three points to get a good results.
I was cutting the brushes and root for almost 3 hours couple days ago to find a suitable location to setup the station where all three points visible. At end of the day I was able to see all three property corners--set by a local PLS--110, 111 and 112
I looks through calculation method mention in the book and realized that SurveyPro could do it all that for me. So I scan through it quickly.
There few things that I don't understand...
1. It is mentioned resection could be done using distant or angle alone or with multiple other variation of the combination. Can I use both angle and distant as I see that as an option in SurveyPro?
2. How many shot should I take for each known points? i.e. what is recommended?
3. Do I need to do direct and reverse shots? I know my 5603 will always miss the remote target lock when it goes reverse. Talk to local dealer a while ago, he said that is how it works.
4. The step by step in in SurveyPro manual is pretty clear then there is this statement..
"When solution available RMS value of the solution will be shown." What is this RMS value?
5. Then it goes on to say if the point is not a good contributor it can be removed. What is the good RMS value that one should look for?
6. A cautionary note in one of the book says that "It should be noted that the resection problem will not have a unique solution if points define a circle." What is this circle?
7. Also learned that the angle of the observed points should be greater than 30 degrees. So I think I have that between all three points. Right?
8. I always work in robotic mode. Can I do this robotic mode or should set up prisms?
I hope this not too many question for single post. Thank you.
yoginatha...
> Aloha,
> I've never done resection before. I want to establish the line for clearing from pt110 to pt111
> There are no other point in line of sight to setup station and do backsight. I only show few large threes but it is over grown a long the line and everywhere. The large tree close to pt111 is a huge Ficus tree with tons of aerial roots. I could traverse over here about a thousand feet away again with a lot of setup and breakdown due to obstacles. So I thought it is good time to learn resection. I read about it and decide I should have three points to get a good results.
>
> I was cutting the brushes and root for almost 3 hours couple days ago to find a suitable location to setup the station where all three points visible. At end of the day I was able to see all three property corners--set by a local PLS--110, 111 and 112
>
> I looks through calculation method mention in the book and realized that SurveyPro could do it all that for me. So I scan through it quickly.
> There few things that I don't understand...
>
> 1. It is mentioned resection could be done using distant or angle alone or with multiple other variation of the combination. Can I use both angle and distant as I see that as an option in SurveyPro?
>
you should if it is available, you will get better results
> 2. How many shot should I take for each known points? i.e. what is recommended?
>
your electronics should display intermeiate results as you go. a good controller will allow you to disable measurements with high residuals
> 3. Do I need to do direct and reverse shots? I know my 5603 will always miss the remote target lock when it goes reverse. Talk to local dealer a while ago, he said that is how it works.
>
you should
> 4. The step by step in in SurveyPro manual is pretty clear then there is this statement..
> "When solution available RMS value of the solution will be shown." What is this RMS value?
root mean squared, it is a quality indicator
>
> 5. Then it goes on to say if the point is not a good contributor it can be removed. What is the good RMS value that one should look for?
>
this depends on you
> 6. A cautionary note in one of the book says that "It should be noted that the resection problem will not have a unique solution if points define a circle." What is this circle?
>
a circle that is circumscribed about the three measured stations
> 7. Also learned that the angle of the observed points should be greater than 30 degrees. So I think I have that between all three points. Right?
>
this is called strength of figure
> 8. I always work in robotic mode. Can I do this robotic mode or should set up prisms?
>
> I hope this not too many question for single post. Thank you.
>
>
>
>
read up on all this, it is readily available on the interwebs. if in doubt, don't do it, and don't work unlicensed. mahalo
Mr monk
Resection from two points , check into the third point with stake out routine . Should be fine for what your doing. Robotic mode should be fine
. Also check into your resection points with stake out routine after the resection . Use stake a line routine to stake your line .
Resection is a more automated form, of getting onto a brg and coord system. I'd suggest that you do it manually, as in, shoot from your traverse point to 2 known points, then rotate, and translate into that system, then inverse to see how much distance error there is. The idea is that it is more time consuming, but you are more in touch with what happened. In your case, knowing what happened has it's value.
N
With what Nate suggest . Always locate your resection points after the resection . If you don't you will not have the true location of the resection points . There is always error the found monuments and record description. If your just trying to stake straight line shoot both corners and use stake a line , don't need resection . But you are taking a risk not hiring a professional to handle the surveying . Lots if crazy stuff can happen . There might have been a surveying monk back in the 60's that shifted the corners 20 feet. Then you will not be in harmony with the true location and the legal record. Anything with the boundary should be handled by a professional.
The "classical" resection is a pair of angles measured betweeen three known points without any distance measurement. (See Problem Corner problem number 30 at profsurv.com for three different ways to solve it.)
Adding distance measurements to your network only strengthens the solution. Your software is what you really want to learn.
Additional clarification...
Thanks Eddie!
> > 6. A cautionary note in one of the book says that "It should be noted that the resection problem will not have a unique solution if points define a circle." What is this circle?
> >
> a circle that is circumscribed about the three measured stations
Let see if I get this right...If draw a circle, all three points should not fit in the circle? See image below... in this case pt110 is not in the circle.
> read up on all this, it is readily available on the interwebs. if in doubt, don't do it, and don't work unlicensed. mahalo
Yes, I will read up on all this. I don't do any work outside of our boundary. Nor any work within the boundary that requires legal work i.e easements etc. Thank you for reminding to stay out of trouble.:-D
Thanks DJames!
Mr. Yogi,
Based on your level of experience, I would suggest that you take the simplest approach. This is usually the best.
Rather than doing a resection, which is one option available to you. With the configuration shown you have another option.
If you have a compass, take a bearing from your total station to 110. This is the longest distance and there for the best for your back sight from your total station setup. Then using the point and direction routine, push a point out from 110 on the reverse of that compass bearing (180 degrees)using the measured distance from the total station to point 110. Store this as a new point, say 200 and make it your occupying point. Now occupying this new point,200 and backsighting 110, turn an angle and distance to 111. Store this as a new point, 201.
Now do an inverse between 110 and 111 and write down the bearing and distance. Next inverse between 110 and 201 and write down this bearing and distance. If the distances come very close, you're good. The difference between the two bearings is what you now need to rotate. So now select points 200 & 201 for adjustment, rotate. The rotation point is 110, because this is the point that is common to your points and the points you are orienting to. The old bearing will be from 110 to 201, based on your compass bearing. The new bearing will be from 110 to 111, based on the coordinates you're orienting to. Think of it as taking your total station along for the ride when you rotate onto the line 110-111.
After rotating 200 & 201 onto 111, do an inverse between 201 and 111 and see how they compare. They should be very close. After doing this, turn an angle and distance to 112 and store a point 202. Inverse these two points as a check. If they match up well, you are now oriented. No resection necessary and you have a much better feel for the quality of the control you're working with.
Good luck. Namaste.
Additional clarification...
> Thanks Eddie!
>
> > > 6. A cautionary note in one of the book says that "It should be noted that the resection problem will not have a unique solution if points define a circle." What is this circle?
> > >
this must be an old(er) book? this concept was generally used when distances were measured with a steel tape, not electronically
no. all three points that you are going to measure. you only captured two of them.
> > a circle that is circumscribed about the three measured stations
> Let see if I get this right...If draw a circle, all three points should not fit in the circle? See image below... in this case pt110 is not in the circle.
>
if you are using angles as well as distances, the three points in the circle concept becomes a non issue. use good judgement, good measurements; garbage in, garbage out.
it appears that the figure you have drafted should work ok for a total station and dist/angles combined
> 1. It is mentioned resection could be done using distant or angle alone or with multiple other variation of the combination. Can I use both angle and distant as I see that as an option in SurveyPro?
If you can measure both angle and distance, why wouldn't you. The more redundancy in measurements you have, the better the precision, and the better to detect any blunders.
> 2. How many shot should I take for each known points? i.e. what is recommended?
I would go for at least a direct and reverse angle, and read several sets of distances. Measuring the angles and distances are the least time-consumming part of a setup in comparison to setting sights over the points and setting up the instrument. I think it would be silly to shoot only one set of angle or distance.
> 3. Do I need to do direct and reverse shots? I know my 5603 will always miss the remote target lock when it goes reverse. Talk to local dealer a while ago, he said that is how it works.
I don't know about missing the remote target lock, but if you can visually aim and get the measurements the better.
> 4. The step by step in in SurveyPro manual is pretty clear then there is this statement..
> "When solution available RMS value of the solution will be shown." What is this RMS value?
9 I see someone answered this.
> 5. Then it goes on to say if the point is not a good contributor it can be removed. What is the good RMS value that one should look for?
Look at the observations and see if including one shot makes the solution a much higher value than if you exclude it. If the combination of shots are all within 0.2' of each other, but if you exclude the largest outlier and it tightens the solution down to 0.02', then I would consider it an outlier and exclude it from the group. Generally speaking something over the mean by 3 times is often considered the outlier.
> 6. A cautionary note in one of the book says that "It should be noted that the resection problem will not have a unique solution if points define a circle." What is this circle?
All measurements have a certain amount of uncertainty. Redundant measures will tighten up that amount of uncertainty.
> 7. Also learned that the angle of the observed points should be greater than 30 degrees. So I think I have that between all three points. Right?
I don't buy in to needing greater than 30 degrees. Especially if you are measuring distances only without angles that factor will play in even greater. Using good technique and redundant measures will factor down the "strength of figure" factor. However a lot of guys would disagree with me on this issue, so it might be best to stick to the >30º rule until you have a better handle on this issue and maybe have run some comparisons on your own. I would say that each interior angle should be greater than 30º; making the wider angle between the extreme points to be >60º (but < 150º)
> 8. I always work in robotic mode. Can I do this robotic mode or should set up prisms?
Set up prisms for greater accuracy, but have your own feel for what kind of precision you need for your particular job. Maybe prisms are more than you need.
> I hope this not too many question for single post. Thank you.
You're allowed at 7 more. (not really; just kidding).
> Resection is a more automated form, of getting onto a brg and coord system. I'd suggest that you do it manually, as in, shoot from your traverse point to 2 known points, then rotate, and translate into that system, then inverse to see how much distance error there is. The idea is that it is more time consuming, but you are more in touch with what happened. In your case, knowing what happened has it's value.
>
> N
Aloha, Nate: I hope you feel better after what appears to be pretty rough dental work yesterday!
I like what you've suggested--this is very good. I am the person like to know what is happening behind what I am doing. This will be a good practice.
If I understand you correctly. I do the resection first. Then get to the location by traversing from known points. Shoot the two or three points then inverse to compare the results. Right?
Thanks
> With what Nate suggest . Always locate your resection points after the resection . If you don't you will not have the true location of the resection points . There is always error the found monuments and record description. If your just trying to stake straight line shoot both corners and use stake a line , don't need resection . But you are taking a risk not hiring a professional to handle the surveying . Lots if crazy stuff can happen . There might have been a surveying monk back in the 60's that shifted the corners 20 feet. Then you will not be in harmony with the true location and the legal record. Anything with the boundary should be handled by a professional.
Aloha, Djames:
Thank you for the good suggestion. I will locate them. I am actually saving all these inputs for my work flow. What a great resource!!!
I actually prefer to stake a straight line. But due to vegetation in the way (not shown in the sketch) and wanting to learn resection inspired me to explore this. While I want to practice this with absolute diligent and precision to set a right habit pattern, this work only meant to define the area need to cleared to have clear line of sight to establish the fence line.
I am a firm believer that a professional service must be use where it should. All my boundary corners were set by PLS**. I have a self imposed rules--don't mess around the boundary and things that require legal recordation. However, I am glad this is being reinforced in my mind by many of you--which is very important--to avoid unnecessary legal troubles for our church. I actually appreciate it.
**The church paid over 7K for one PLS to set our property corners about five years ago. Church owns multiple parcels abutting each other. Somehow the way he set it, two of the parcel's boundaries were overlapping each other by 8 ft at one end! Another when into a building by 3ft. While previously set pipe in the 70's is found exactly 5' away from the building which was ignored. I was just another survey illiterate client...:-D Then I begin to educate myself in this area. Make the long story short...with input form couple us here in this forum, we ended up hiring another PLS to retrace the boundary lines. FWIW, the line that I am working on fortunately set by another survey and matches several of the found monuments.
I am seeing what I think Nate is saying, or at least my interpretation of the same. I would possibly turn the angle between two of the points and measure the distances using a prism, and I would pull out my calculator and apply the formula
c²=a² + b² - 2(ab)(cos C)
Where (lowercase) c is the unknown distance, capital C is the angle you are measuring and a and b are, for instance, the measurements to points 110 and 111 - two sides that you measure. See how well your calc'd measurement "c" matches the called-for distance on the plat (that would be your measured distance of the unknown line). Do the same for the two other triangles and make the same calculations. (ie: you just solved for triangle 110-C-111, now do triangle 111-C-112, then do 110-C-112). Each of those will give you a different solution for where your point "C" is when you hold your bearings between the "known" points. This will supply a "cluster" of points for "C". that is your "error circle".
I hope that made sense in the way I worded it.
> Mr. Yogi,
>
> Based on your level of experience, I would suggest that you take the simplest approach. This is usually the best.
>
> Rather than doing a resection, which is one option available to you. With the configuration shown you have another option.
>
> If you have a compass, take a bearing from your total station to 110. This is the longest distance and there for the best for your back sight from your total station setup. Then using the point and direction routine, push a point out from 110 on the reverse of that compass bearing (180 degrees)using the measured distance from the total station to point 110. Store this as a new point, say 200 and make it your occupying point. Now occupying this new point,200 and backsighting 110, turn an angle and distance to 111. Store this as a new point, 201.
>
> Now do an inverse between 110 and 111 and write down the bearing and distance. Next inverse between 110 and 201 and write down this bearing and distance. If the distances come very close, you're good. The difference between the two bearings is what you now need to rotate. So now select points 200 & 201 for adjustment, rotate. The rotation point is 110, because this is the point that is common to your points and the points you are orienting to. The old bearing will be from 110 to 201, based on your compass bearing. The new bearing will be from 110 to 111, based on the coordinates you're orienting to. Think of it as taking your total station along for the ride when you rotate onto the line 110-111.
>
> After rotating 200 & 201 onto 111, do an inverse between 201 and 111 and see how they compare. They should be very close. After doing this, turn an angle and distance to 112 and store a point 202. Inverse these two points as a check. If they match up well, you are now oriented. No resection necessary and you have a much better feel for the quality of the control you're working with.
>
> Good luck. Namaste.
Aloha, Williwaw:
Now, I have good homework to work on. I will explore this method and what you described is pretty clear. The iPhones have true north compass. I assume that would be okay?
Thanks!
Back 2 Basics--Resection>Yswami
So, do you have an good gluten free pizza dough recipes??
"Swami helps take care of the monastery's herd of dairy cows, and on retreats loves to prepare special meals and creative hot sauces for his brother monks, not to mention his bread- and pizza-making gifts."
and I'd be interested in those hot sauces, too!
Back 2 Basics--Resection>Yswami
Don,
You have Siddhanathaswami (pizza) confused with Yoginathaswami (surveyor).
I like both pizza and surveying...
DDSM 😉
Back 2 Basics--Resection>Yswami
> So, do you have an good gluten free pizza dough recipes??
>
> "Swami helps take care of the monastery's herd of dairy cows, and on retreats loves to prepare special meals and creative hot sauces for his brother monks, not to mention his bread- and pizza-making gifts."
>
> and I'd be interested in those hot sauces, too!
Aloha, Donald:
The description above I believe is for another monk in the monastery...
However, I mostly do wholewheat bread. However, one other monk did wheat free pizza. The crust will be a bit hard--difficult to section it into pieces it may required multiple resectioning:-D . Hot sauce is my area. Of course we can share the recipes. I can email to you or post it separately.
let me know
> I am seeing what I think Nate is saying, or at least my interpretation of the same. I would possibly turn the angle between two of the points and measure the distances using a prism, and I would pull out my calculator and apply the formula
> c²=a² + b² - 2(ab)(cos C)
>
> Where (lowercase) c is the unknown distance, capital C is the angle you are measuring and a and b are, for instance, the measurements to points 110 and 111 - two sides that you measure. See how well your calc'd measurement "c" matches the called-for distance on the plat (that would be your measured distance of the unknown line). Do the same for the two other triangles and make the same calculations. (ie: you just solved for triangle 110-C-111, now do triangle 111-C-112, then do 110-C-112). Each of those will give you a different solution for where your point "C" is when you hold your bearings between the "known" points. This will supply a "cluster" of points for "C". that is your "error circle".
>
> I hope that made sense in the way I worded it.
Aloha, Tom:
It make sense to me. All the suggestion will keep me busy for several days (since I do have other duties to attend to...)
"Error circle" is the technical term for minimum and the maximum possible errors. Right?
Thanks
> Aloha,
> I've never done resection before. I want to establish the line for clearing from pt110 to pt111
> There are no other point in line of sight to setup station and do backsight. I only show few large threes but it is over grown a long the line and everywhere. The large tree close to pt111 is a huge Ficus tree with tons of aerial roots. I could traverse over here about a thousand feet away again with a lot of setup and breakdown due to obstacles. So I thought it is good time to learn resection. I read about it and decide I should have three points to get a good results.
>
> I was cutting the brushes and root for almost 3 hours couple days ago to find a suitable location to setup the station where all three points visible. At end of the day I was able to see all three property corners--set by a local PLS--110, 111 and 112
>
> I looks through calculation method mention in the book and realized that SurveyPro could do it all that for me. So I scan through it quickly.
> There few things that I don't understand...
>
> 1. It is mentioned resection could be done using distant or angle alone or with multiple other variation of the combination. Can I use both angle and distant as I see that as an option in SurveyPro?
>
> 2. How many shot should I take for each known points? i.e. what is recommended?
>
> 3. Do I need to do direct and reverse shots? I know my 5603 will always miss the remote target lock when it goes reverse. Talk to local dealer a while ago, he said that is how it works.
>
> 4. The step by step in in SurveyPro manual is pretty clear then there is this statement..
> "When solution available RMS value of the solution will be shown." What is this RMS value?
>
> 5. Then it goes on to say if the point is not a good contributor it can be removed. What is the good RMS value that one should look for?
>
> 6. A cautionary note in one of the book says that "It should be noted that the resection problem will not have a unique solution if points define a circle." What is this circle?
>
> 7. Also learned that the angle of the observed points should be greater than 30 degrees. So I think I have that between all three points. Right?
>
> 8. I always work in robotic mode. Can I do this robotic mode or should set up prisms?
>
> I hope this not too many question for single post. Thank you.
>
>
>
>
I think a resection as you are mentioning it here is a poor idea. I would create a dummy set of coordinates, calling your instrument 2, backsight on the Western end of the 334' line, and turn into the Eastern end of the 334 foot line. Then, rotate and translate those values and voila, you're on his bearing base and relative. You can then check into the third point.
The reason I think it's poor is there is a poor angle of incidence between the Northern end of the 40' line and the Eastern end of the 334' foot line. I'd use the KISS principle here and roll on.
Also, keep in mind that you're resecting into someone else's work with maybe some knowledge of the procedure, but that doesn't mean that the stakeout was very good. I'm not trashing his name, but you can survey better than you can lay out, so always, when available, tie into what the other guy found, not what he set.
