GEM 3330
Advanced Measurement Analysis
Web Page
Prof. Dave Gibson
304 Reed Lab
352-392-4995 Ofc
352- 591-2804 Home
DISCUSSION NOTES:
Sat. Jan 7 WELCOME TO ADVANCED MEASUREMENT ANALYSIS. I enjoyed my first Saturday with the class, and I enjoyed meeting all of you.
Lab#1 20 Measurements is assigned. Write it up in MSWord and attach it to an email back to me by the end of Saturday, Jan 14.
Lab #2 Theodolite Random Errors is assigned. Write it up and have it ready to turn in at my next visit, Jan 21.
Tues, Jan 10 My response Take means of clusters and plot them on a x-y plot with the vertical axis being the value and the horizontal axis being the number in the "clusters" that you take the mean of. You plot your 20 values above the "1" on the horizontal axis (each is a mean of 1 value). Then cluster the measurements taking two at a time: 1st and 2nd, 3rd and 4th, etc., taking the mean of each cluster. Plot these 10 means above the "2" on the chart. Then mean readings taking four at a time for 5 clusters, plot these. Same for five at a time (four clusters), plot these means -- then 10 at a time for 2 means -- then 20 at a time for one mean. Question from a class member: Dr. Gibson some of the guys in class are having trouble understanding step 5b (demonstrate the law of compensation) in the lab. Could you please explain this in more depth. For the most part the problem is that we do not know which data to "mean" all of it, or certain clusters of data and if clusters which clusters
Wed, Jan 11 My response -- You are to find the least squares adjusted value by trial and error. Pick a trial adjusted value near the middle region of the measured values. Subtract this from each reading and then square the difference. Add all 20 squared differences for the quantity "U". Then try another trial adjusted value, compute U. Try another, compute U. Keep trying till you find the value that gives the minimum U. That's the "least sum of squares" adjusted value. Let me know how it goes. OK? The question: Yes the resonse helped very much and I was able to progress to the part about the least squares adjustment however I am having trouble understanding this part also(what is the adjusted value and how do we know if the mean gives the least square). I have been reviewing some of my statistics books and cannot find any examples can you explain this also. With luck I hope to have my completed lab e-mailed to you by this afternoon or thursday morning.
Mon, Jan 16th I've now graded and returned Lab1. I look forward to being in Troy this coming Saturday 1/21 for our second meeting.
Tues, Jan 17th At the beginning of the class period 9AM Saturday 1/21, we will have Quiz1Lect1, Quiz2Lab1, and Quiz3Lect2, three questions on each quiz. The questions will be mostly multiple choice. These three quizzes will not involve text coverage, but all quizzes after these will involve text reading and problems.
Fri, Jan 20th A class question and my response: Response: Read the horizontal angles only. For Er, just sight the target and press the "Meas" button 20 times. They may all be the same, or may differ, then take the std dev. For Erp, use the tangent screw to take 20 pointings on the target reading the horizontal angle for each, calc the standard dev. For Erpc, put a target on a tribrach at a known distance from the instrument, center the target over a marked point, point the total station, center the target and read the horizontal angle 20 times, calc the standard deviation. For Erp-pc, hold a prism on a marked point a known distance from the instrument, center the prism and read the horizontal angle 20 times, calc. the std dev. Then follow the lab assignment for more details. OK? THE QUESTION: Dr. GibsonI am have a problem understanding which measurement i should take the standard deviation of in the Teodolite Random Errors lab #1, 2, 3, and 4. Is it the horizontal angle, vertical angle, or the distance? Or maybe all of them?
Fri, Jan 20th A class question and my response: MY RESPONSE For #2, I'd like you to apply the Law of Accumulation. I went through a similar calculation in lecture. The result is a +/- tolerance on the angle measured under the stated conditions. You have one instrument centering "wobble" affecting a sight of 15 ft -- take the wobble and convert it to seconds by arctan(wobble radius/15). This a +/- angle tolerance created by the instrument centering when sighting the 15 ft sight. You also have a similar +/- angle tolerance when sighting the 1000 ft foresight caused by the instrument centering wobble = arctan(wobble radius/1000), express in seconds. You also have a combined error of pointing and reading on the backsight target. You also have a combined error of pointing and reading on the foresight target. You also have a +/- angle uncertainty caused by the prism wobble on the 15 ft backsight = arctan(prism wobble radius/15) You also have a +/- angle uncertainty caused by the prism wobble on the 1000 ft foresight. Once you determine a +/- seconds tolerance for these six individual sources of randomness, then apply the law of accumulation for the combined effect of all for the answer. See you soon, THE QUESTION: Will you please go into detail about part 2 in the conclusion section in Lab 2?
Mon, Jan 23rd I've now posted the three lectures and labs. I've also entered your quiz grades on the spreadsheet. I'll grade Lab#2 soon and post it. I'll see you on Feb 11th.
Thurs, Feb 2nd Good, two students submitted Lab 3 and 4 by email today. All students should have these two in by email by this coming Monday. That will give me time to grade and return. However, I returned the submitted labs to both students because they recited the results only in short statements. I'd like each student to independently write a report of procedures, calculations, results, conclusions. OK?? The class may turn in Lab 5 (Level Testing) by hand at class on Feb 11th.
Thurs, Feb 2nd I've just finished grading and posting grades for Lab2. I've given a lot of "resubmits". This means I'd like it redone and turned in again for a grade. I had a lot of questions while reading the labs. I'll mail these to Steve tomorrow Fri, and you should have them on Monday. Please try to resub by email before Friday next week. OK?
Thurs, Feb 9th Just a note to confirm our upcoming class this Saturday, Feb 11th 9AM. We have a lot to do. We'll review Labs 2, 3, 4, and 5 and then continue lecturing new topics. I've given quite a few "resubmits" to class members. This is my way of coaching the lab write ups into an acceptable form. I just want them to be self-explanatory. See you soon.
We start the class with a 18-question quiz covering (including the text and problem coverage): Lab 2 Theodolite Random Errors, 3 questions, Lecture 3 Theodolite Systematic Errors, 3 questions, Lab 3 Theodolite Testing, 3 questions, Lecture 4 EDM errors, 3 questions, Lab 4, EDM Testing, 3 questions, Lecture 5 Leveling errors, 3 questions (we'll test Lab 5 Level Testing next time)
Fri, Feb 10th: A Lab5 inquiry: MY RESPONSE: TDE is True Difference in Elevation. Since the first setup is midway between the points, both rod readings will be in error by the same amount. Therefore their difference = TDE For the second setup, since the near rod is very close to the instrument, it is considered without error. Combining the near rod reading with the TDE computes the far rod reading that you should have if the level has no collimation error. By subtracting the actual far rod reading from the "perfect" far rod, you can see the amount of inclination in the level line of sight, and compute the C factor as the slope of the line of sight in ft/ft units.Hope this helps. THE QUESTION: I am having a little bit of a problem with number one(Perform a Peg Test on the level)on lab five. I am not exactly sure what is meant by TDE. Is it the difference in rod reading "A" and rod reading "B"? How is this applied to near rod reading "A" to compute perfect rod reading "B"? I have done some searching in the text book, my notes, and your lecture notes but am not able to find this. Thanks
Wed, Feb 15th: A Lab 6 inquiry: MY RESPONSE: OK, no problem. We'll be reasonable of when it's due considering the timing of that demonstration. OK? THE QUESTION: Dr. Gibson I mentioned to Dr. Ramroop that we would be needing the GPS later this week so that the class could start on the lab. He stated that he would like us to wait to use the GPS because a surveyor is going to come in a few weeks to give a demonstration with topcon equipment and that he was reluctant to let us use it until after the demo because he himself had no experience with the GPS. Dr. Ramroop said to let you know what was happening and asked what you thought of the new info.
Mon, Feb 20th: I was out of town last week, so today I've posted labs 6 and 7. You can start these at any time in either order.
Fri, Mar 3 I'll be there for our class tomorrow 9AM-5PM. We'll (1) take quiz -- this quiz will cover Lab5, GPS1 and GPS2 lecture outlines as posted for the last several weeks. However, this quiz will concentrate on the text coverages for the lectures. (2) We'll set up the GPS and take a file and demonstrate how to upload it to OPUS as a helper for Lab 6. (3) We'll go outside and run a class demonstration on 3-wire levels, again as a helper for Lab 7. (4) We'll lecture on new material. OKEY DOKEY??
Thurs, Mar 16 I've just posted the Trigonometric Leveling Lab as we discussed at our last meeting. I'm looking forward to our April 1 meeting.
Thurs, Mar 30 Here's what we'll do in class Saturday, April 1: (1) take quiz -- Lab 7 (three-wire leveling theory), Lecture: Basic Geodetic Concepts (see text coverage and problems): Lecture: Level Theory and Trigonometric Leveling (see text coverage and problems) (2) I'll bring GPS equipment, we'll set it up, record a static session, download the data in to the computer lab as your source data for Lab 6 (3) lecture on new material -- astronomic observations for azimuth.
Mon, Apr 3: As discussed in class, the FINAL exam will be proctored by Dr. Ramroop at a time convenient to him and the class. The discussed date is on Friday, April 21st in the afternoon. For the OPUS lab, you may download the RINEX file from this website. Here is a link to the FINAL study review questions: here.
Fri, Apr 14 I've mailed the final exams to Dr. Ramroop. He indicated by phone that the final will NOT be on April 21, but on Wednesday, April 26th because of the ACSM conference. Please coordinate with him to make sure of the proper time and location.
NOTE: The final will be OPEN LABS, NOTES, and TEXT. You can use any of our course materials as open notes for the exam (except your class members).
Wed, Apr 19 I've posted the results of Gary Kolb's Polaris observation. The class should set up on the 100 m point and backsight on the base point on our 3-wire level points. Then I'll post all the results on the "CLASS RESULTS" spreadsheet, posted below near the Polaris lab. OK?
Thurs, Apr 20 I've posted the grades spreadsheet (without updating the averages). It should be current through today. If something's not right, let me know. I also posted the updated Polaris class results. Very good!!
Fri, Apr 21 I've now received the first OPUS lab. I've posted below a OPUS CLASS RESULTS spreadsheet. Please all other students present two documents (1) put your data in the CLASS RESULTS spreadsheet and attach it so I can post, (2) a MSWord doc explaining your procedures and conclusions. Also include your OPUS output sheets.
Thurs, Apr 27 Well, I hope the final went OK, I'll be getting the finals from Dr. Ramroop and grading them pronto. I'll post the grades on our spreadsheet. THE LAST TIME FOR GETTING ANY LABS OR RESUBMITS IN IS: Tuesday, May 2, 5PM. OK??
Wed, May 3 I've now graded the last lab submittal. Do not send any more. The deadline is past.
Thurs, May 4 I've now posted the final grade sheet with the final grades to be assigned. I've enjoyed the class. Best wishes to you all.
Thurs, May 4th 6PM I've now submitted the grades according to the last version of our grade sheet below.
LECTURE OUTLINES:
Lecture: Theory of Measurements: here
Lecture: Theodolite Random Errors: here
Lecture: Theodolite Systematic Errors: here
Lecture: EDM Theory/Constant Errors: here
Lecture: EDM Systematic Errors: here
Lecture: Level Theory and Errors: here
Lecture: GPS#1 Theory: here
Lecture: GPS#2 Theory: here
Lecture: Basic Geodetic Concepts: here
Lecture: Leveling Theory and Trigonometric Leveling: here
Lecture: Astronomic Observations for Azimuth: here and here
Upcoming Lectures:
ASSIGNED LABS AND HOMEWORK:
Lab1 20 Measurements: here
Lab2 Theodolite Random Errors: here
Lab3 Theodolite Systematic Errors: here
Lab4: EDM Testing: here
Lab 5: Level Testing: here
Lab 6: GPS OPUS: here, NGS control points near Troy: www.ngs.noaa.gov datasheets Lat: 31.831, Long: 85.966 west. OPUS CLASS RESULTS SPREADSHEET: here
Our Fire Hydrant Rinex file: here
Lab 7: ThreeWireLeveling: here
Lab 8: Trigonometric Leveling: here
Lab 9: Polaris Observation for Azimuth: here Spreadsheet: here CLASS RESULTS: here
Upcoming Labs:
Course Resources
Syllabus and Calendar: here
PROGRESS GRADES: here