How to run a Level Loop using a Differential Level
The purpose of this video is to introduce the viewers to setting up a survey differential level and the processes of leveling to order to find the elevations of points. The survey level does not require batteries and functions by taking the differences in elevations between points. This video has two parts, the set-up process and leveling between points.
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Part 1 - Setting up a Survey Level
Our level will be set up on an arbitrary point between the points we want to set up. One of these points is known as the Benchmark. This benchmark is established by either you or an older surveyor. The benchmark has a known record elevation, whether it is public record or your own records. The level is set up on a survey tripod and is leveled by adjusting the knobs on the bottom of the level. These knobs will move a bubble on the level around. We need this bubble to be leveled in the center to ensure our level is flat with the surface of the earth.
Part 2 - Using our Difference Level and Philadelphia Rod
Once your level is leveled out, we can begin collecting data. Our initial reading will be on the benchmark. This will be considered our backsight reading. Using a Philadelphia Rod, we will measure where our cross hairs lay to find the difference between the ground elevation and the instrument height. The red numbers on the rod indicate feet, the large black numbers are the tenths of a foot, and the dashes in between indicate the hundredths of a foot. After taking the backsight reading on the benchmark, you will then add this to the elevation to get the instrument height. Then move to the next point and measure a foresight. This foresight is subtracted from the instrument height to give us a new elevation. In the video, we took a turn point by the gate to move closer to our sight. After finding the elevation, we moved the level towards the site. We reset the level and took a back sight on our turn point by the gate. With the new backsight reading, we then add it to the elevation of the turn point to find the new instrument height. After that, we took three side shots or rod shots on points green, orange, and blue. All of these are also considered foresights and should be subtracted for our second instrument height. Once we measure all the points, we will foresight the turn points again, move the level to an arbitrary location between the turn point and our original benchmark, relevel, backsight the turn point and foresight the benchmark. If all was done correctly, our elevation on the benchmark should match that of the record elevation.
About Professor Rami Tamimi:
Rami Tamimi is an American doctorate student at The Ohio State University working towards his Doctor of Philosophy in Geodetic Engineering. With over 8 years of experience in the Land Development Industry, his experience revolves around traditional field surveying, civil design work using AutoCAD Civil 3D, and geospatial technology including LiDAR, SONOR, and Photogrammetric data acquisition and processing with the use of Unmanned Aircraft Systems or Drones. He is also a University Professor and creates instructional video content on KZread.
Intro: (0:00)
How Differential Leveling Works: (0:21)
Leveling between Points: (7:18)
Outro: (12:03)
#Surveying #Leveling #Differential
Пікірлер: 73
I have been surveying 51 years (36 years licensed). I trained many "green" Rodman. I taught surveying and cadd classes at 3 local community colleges for over 15 years and then taught continuing education classes for license renewal. Your videos are extremely well done and very educational. They would be a great tool for training young or old future surveyors. Thank you producing a great training tool. I would have loved having something like this 50 years ago when I began my survey journey
I have learned more from two of your 12 minute videos than an entire semester of my surveying class. Awesome. Thanks.
@RamiTamimi
3 жыл бұрын
Glad to help!
Explained this better than my college instructor. Thank you!
I have no words! This is impeccable work! God bless!
I’m just starting to learn to run the gun at work this is very helpful. Thank you
Great breakdown, great edit and showed how simple Level Runs are. Very well done!
@RamiTamimi
3 жыл бұрын
Thank you, glad you liked it!
Thank you for taking your time to create these videos...they are so helpful
@RamiTamimi
2 жыл бұрын
You are so welcome!
great explanation, hard to learn just by reading so it helps that you illustrate
@RamiTamimi
3 жыл бұрын
Glad it was helpful!
Good job! Love these videos.
@RamiTamimi
2 жыл бұрын
Glad you like them Leyla.
Dude,..... You are amazing
@RamiTamimi
3 жыл бұрын
Thank you so much 😀
Thank you so much
Great job
@RamiTamimi
2 жыл бұрын
Thanks!
Great as usual, but a drawing at the end of the video showing these steps and relevant values will be very useful. Thanks, Rami..
im very thankful u make videos about this subject since my instructor never gave us a lecture regarding it especially now that it's online class
@RamiTamimi
3 жыл бұрын
You are very welcome, I'm glad I am able to help!
Dude you busted your level loop
بسم الله ماشاء الله مهندس رامى
@RamiTamimi
2 жыл бұрын
الله يبارك فيك يا غالي
@adelsamak2418
2 жыл бұрын
حبيبى يا كبير
Nice
@RamiTamimi
3 жыл бұрын
Thanks!
Dear Rami thanks for the informative videos. In your current video at time 8:40, when you are ready to go to the next point, I think it would be better if you go right under the tripod and carry it on your shoulders. In your case, the level could fall on the ground.
Hi Rami, thanks for the great video. If working alone is it fair to say that the same results could be obtained by using a 360 external laser level with a laser receiver mounted to the levelling rod?
Really appreciate 😊 and editing is on point .How are there two of you at same time or do you have a twin that dresses exactly same 🧐🧐🧐
@RamiTamimi
3 жыл бұрын
Haha, I used an editing trick called masking. Glad you liked it!
@xdeepak12
3 жыл бұрын
@@RamiTamimi love it and can you please make a video about cross section leveling and also how to plot on graph . Appreciate the work 😃😃you make it so much easier to understand. Thank you.
@RamiTamimi
3 жыл бұрын
Yes I've made a video about sectional leveling, or Profile Leveling. Here is the link: kzread.info/dash/bejne/X4dlqK2cZ7iWoto.html
@MatthewKigen
3 жыл бұрын
@@RamiTamimi that guy is slow he should be fired .haha..
Don't let them move the rods from the turning point while you are moving the instrument! Always have the rod holder use a rock or high point of hard ground as a turning point.
@Rami Tamimi - Yours are the best videos I've watched on surveying/total stations, thank you. One question: You mention a few times that you know the elevation of the manhole. This is crucial because this is required to determine all other elevations. Therefore, my question is -- Can you explain how/where a person *finds* the known elevation of landmarks, such as manholes? Thank you in advance!
@RamiTamimi
3 жыл бұрын
Usually known elevations are given though a federal agency. In America, most benchmark elevations are given from the National Geodetic Survey (NGS). If you don't know your elevation, you should assume your elevation and then adjust all the relative elevations in the office.
@pmcleod6844
2 жыл бұрын
asbuilt construction dwgs will have elevs..good for a quick check..dont rely on them though..
Hey Rami, I noticed you using a very nice quality set of chaining pins or arrows in one of you videos, where did you find them? I would love to have a set just like them.
@RamiTamimi
3 жыл бұрын
I just bought them from my local surveying supply store. They do sell them on eBay and Amazon as well.
thank you .I noticed the readings in your booklet on TP1(gate) on closing the loop changed from 3.79-4.35(for back-sight column) and 4.50-3.75 (on foresight column) on time stamps 11:45 and 11:57 , is this justified ?
@michaeldiongco3851
2 жыл бұрын
yeah ive notice too
hi their im presently working on a construction site in guyana as a carpanter but i was assigned to work as a chain man but im using a bumpie level but my field note is not how it supposed to be noted can u please help me out in my firld notes
why do you seem to be trying to take imperial measurements in metric form? did i miss you explaining that somewhere?
Can u do open differential leveling.. And make calculations using excel Tnx.
Hey Rami why surveyors don't use total station for elevation loops, only eye levels? Thanks
@r.c.l2569
Жыл бұрын
Because of accuracy
In my opinion if you plump the leveling back and forward holding the rod like that you end up getting error, unless there is a bubble that indicates level is straight to precisely level it. No problem with your method tho.
@RamiTamimi
3 жыл бұрын
The ideal method is always to use a bubble, however, in the field, we have to have methods that will solve problems like leveling the rod without a bubble. Hence rocking the rod is what we do in practice when a bubble isn't present.
@bdm3056
3 жыл бұрын
@@RamiTamimi just buy a hand level and the Rodman keeps it on him. Simple. Got to have the tools to do the job correctly.
@bdm3056
3 жыл бұрын
Why don’t you read thousands? Why don’t you level the tripod legs? Why is your instrument so low? I’m an instrument man and if my boss sees my tripod leaning to one side like yours was I’ll get in trouble. Can’t do that in the construction sites I go to
@RamiTamimi
3 жыл бұрын
@@bdm3056 my level rod has a precision of only 5 thousandths, and industry-standard is usually the nearest one-hundredth of a foot. You could level the tripod legs, however for a differential level, it's not critical, total station would be more critical. My instrument height doesn't really matter since we are calculating the height of the instrument using the backlight reading to the benchmark. Whatever height you set it to should be comfortable for you, this height is what I am used to. My equipment was not leaning, I leveled it on camera. 😊
Sir, how do you know the known elevation of first benchmark (BM1) as 795.00 ?
@RamiTamimi
3 жыл бұрын
Great question. This is given information. If you do not have a known Benchmark, then you can assume an elevation of 100 feet and work relative to this assumed elevation.
@ashbelrovins3399
3 жыл бұрын
@@RamiTamimi Ok Thank you sir😃😃😃
Sir, can u tell me how a surveyor calculates the Benchmark of a particular place?
@RamiTamimi
3 жыл бұрын
Benchmark elevations are generally given through record. Now if you don't have the record elevations, you may also assume the elevation and then adjust in the office.
@ashbelrovins3399
3 жыл бұрын
@@RamiTamimi ok sir
@pmcleod6844
2 жыл бұрын
each town, city, or state province have a database that Is free for all to use..
3:54 I've never heard a grade rod called a Philadelphia rod in my entire life. Where does that name come from?
Сразу видно что привык на тахеометре работать. Прибор низко ставит😊
It's hard to find good chainmen these days :P
Too bad you forgot to mention the upper and lower croshair. Count these readings together and devide by 2 to check your final Reading. Also, you van check the distance. Keep up the great work!
واضح انك عربي شغال عندك من امتي ؟
@RamiTamimi
2 жыл бұрын
أنا أمريكي من أصل فلسطيني وأعيش في أمريكا.
@aballahec5517
2 жыл бұрын
طيب مهنة المساحة مطلوبه في امريكا هينفع اقدم عليها ؟؟
Philadelphia rod lol
no size
@RamiTamimi
2 жыл бұрын
?
At the begin you gave the opposite way to read js fyi the phil stick ,
Just use meters. Holy crap, it’s the 21st century.
ur looking at the script to talk.