How does land surveying work?
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How does land surveying work?


We use all kinds of measuring tools in our
everyday lives: rulers, protractors, squares, and tape measures, etc.. These work fine for small- and medium-sized
projects, but what if we need to layout something big like a road, bridge, dam, or pipeline? Hey I’m Grady and this is Practical Engineering. Today we’re talking about one of the civil
engineer’s most important companions, land surveyors, and we’re also going to try a
little bit of surveying you can do at home. This video is sponsored by Blue Apron, more
on that later. Surveying is essentially the science of taking
big measurements, and you’ve probably seen these guys on the side of the road looking
through fancy equipment on a tripod. Just about any civil engineering project starts
with a survey to determine the legal boundaries between parcels of property, the location
of existing infrastructure, and the topography and slopes of the land. Humans have always had a penchant for building
big stuff which means surveying is career full of history and tradition. Behind every wonder of the ancient world was
an ancient geometry nerd who laid out the angles and alignments during construction. Surveying is also how we created accurate
maps of the continents like the Great Trigonometrical Survey of India, which took almost 70 years
to complete. I personally think everyone should aspire
to accomplish something in your life that can be prefixed with the words “great trigonometrical.” The ubiquitous tool for a survey is called
a theodolite, and it’s one job is to measure the angles between two
points. Combine those angles with distances from a
chain or tape measure, and you can triangulate the location of any point using trigonometry. Modern theodolites, called total stations,
can not only measure angles, but distance as well, and they have on-board computers
to do the calculations and record the data for later use. When you see a surveyor peering through a
funny telescope, it’s probably a total station, and he or she is probably sighting a reflector
to record the location of a point. That’s just scratching the surface of sophistication
with modern surveying equipment. With GPS and unmanned aircraft, things can
get a lot more complicated. But I’ve got a few ways you can do your
own topographic survey with fairly basic and inexpensive tools. Maybe you’ve got a drainage issue on your
land, maybe you’re planning a landscaping project, or maybe you just want to exercise
your god-given right to take measurements of stuff and write those measurements down
on a clipboard. That’s my kind of recreational activity. My goal is to perform a leveling survey of
my front and back yard, which is just a way to get the relative topography for an area. I laid out a grid of points on a map of my
house and then transferred those points to real life using pin flags. Now I just need to pick my datum or base point
and measure the relative difference in height between that point and all the others. I tried a few ways to do this and there are
no sines, cosines, or tangents required. First, a sight level which is essentially
a combination of a telescope and a spirit level. To use it, first get a buddy or a willing
spouse to hold a surveying rod on the point of interest. Now, look through the sight at a surveying
rod and raise or lower the end until the bubble is centered on the line. Once it’s centered you know that you’re
looking at a point that is exactly level to your eyes. Simply subtract the height of your eyeline
with the height measured on the rod and that’s your elevation. It’s not a precision technique, but it is
cheap and simple which the most you can usually hope for in any part of a home improvement
project. The next way I tried is a water level which
is literally just a length of clear vinyl tubing filled with a liquid. As long as there are no bubbles or kinks in
the line, the free surface at each end of the tube will self-level. I kept one end at my datum a fixed height
and measure the height of the water at the other end as I carry it around to each of
my points. It’s a little more unwieldy but it does
have a distinct advantage, no line of sight required. You can use this method around corners or
behind trees with no problem, and again, it’s a cheap and simple solution. The third method to take a level survey worked
best for me: my laser level. Here’s the thing: I really like lasers. I relish any chance I get to use them in a
constructive way, and this is perfect. The laser level creates a perfect horizontal
line that can be used to line up cabinets or tile, but it is also easy read on a surveying
rod. You don’t need a helper, but you do probably
need to wait until dusk unless your laser is really bright, or you have these sweet
laser enhancement glasses. This isn’t the cheapest solution for a DIY
land survey, but it is the fastest one I tried, and it’s a tool a lot of people already
have. Surveying is one of the oldest careers in
the world, and also one of the most important. Why? Because land is important. If you own some, it’s probably your most
valuable asset, and even if you don’t, you’re pretty much stuck to it no matter where you
go. As a career, surveying is a fascinating mix
of legal knowledge, field work, and technical challenges. And since most civil structures are too big
for conventional measurement tools, the surveyor is one of the most important companions for
the civil engineer. Thank you for watching, and let me know what
you think! Thanks to Blue Apron for sponsoring this video. We are still in the process of getting settled
into the new house. After a long day installing lights in the
workshop or throwing away all the junk left by the previous owner, it has been really
nice not to worry about groceries. Blue Apron delivers all the fresh ingredients
you need, right to your doorstep, in exactly the right proportions to create delicious
recipes at home. If that sounds like something you’d be interested
in, the first hundred people that click the link in the description will get 3 meals free
with their first order. If you like it, you can continue your subscription,
and if you don’t, hey, you just got three free meals shipped right to your doorstep. Again, thanks for watching, and let me know
what you think!

100 Comments

  • gerarbendfeldt

    Thank you, I love science and I love architecture (I am an architect) really appreciate your videos. Greetings from Guatemala!

  • npcrah

    Does anyone know if his "laser enhancing glasses" are real? I would think glasses made to enhance sight of a red laser would not be tinted red… I know our good friend here is not one not to trust, but he is one whose dry wit sarcasm and jokes can sometimes pleasantly drip into his script.

    Preemptive edit: "'pleasantly drip' ^ QFT" I know I know.

  • Bibis Martinez

    well Im From Mexico & sometimes I Help to my father in law to make the surveys …. Too many american people need our work & For me is really hard coul express a technical vocabulary ´cause I dont speak english (Im trying to learn by myself) So This Is the video I have been needing. Thanks

  • Karl Lober

    great thanks .. what website or google site can I use to draw a plat map from the legal description.. I have a survey map but it does not show all the headings .. it just says "Westerly" and the distance "more or less on one side" ..

  • Nicholas Jordan

    An old; known; prank that i advise against is get suited up like this they lay offsets for a 4 lane divided HWY heading for someones very valued property of some kind

  • Oddball 2012

    I surveyed my land in 40 seconds. How? I live in the crappy UK where your garden is bigger than my neighbourhood.

  • Michael Kenyon

    now if they can only explain to me why things dont line up with cogo when we are all using the same projection

  • Jon Pilchard

    you could also use a magneto telluric survey or a geophone in special cases like finding precious elements in a given area

  • Richardatf

    Excellent job on this video Grady, this is such a fascinating and varied subject it must have been hard to trim it down, but you did awesome, love yer stuff.

  • Megakoresh

    I have to say – being a surveyor sounds exceptionally boring. I remember the students from civil engineering faculty doing labs with the total station and it always looked like all they had to do was perform the exact same actions over and over again for hours to get the highest possible level of precision. Consult some map -> place equipment -> measure -> scribble something on paper -> repeat x100.

  • Joshua Tree

    I just assumed my job was to set up pink sticks so excavators could knock them over 😉. Thanks for calling us companions Grady if only all Civil Engineers thought that way 👍.

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  • GSA Architectural & Mechanical Drafting Inc.

    Thank you very much for sharing this video. I am a draftsman and I rely on the surveyors report to know the size, boundaries and shape of a lot in order to know where to place the house I design because the contractor needs to know the setbacks along with other details from my site plan….

  • Day Sena

    Hi, you made a good video here. Do you know more about how can we use the cellphone apps to do this? I would like to know if the mobile topographer can help us to do this as a cheap method. I'm sorry my english

  • marsen cat

    I could not believe it, but that guys gave me step-by-step guide how to make money on surveys. I get paid for 1100 already. Watch their video for details here! OPINION. XCOURSE. XYZ

  • Edward Varby

    I used a laser atop a level atop a yardstick & a small helper to prove that my old house's kitchen was 6" lower on one side. many other rooms were uneven too I might have mentioned it on a video about soil..

  • Oliver Allen

    These videos are so boring. I have also watched all of them. I'm just sat here waiting for the next video now.

  • Rico Cordova

    It's funny because I was wondering about surveying on my bike ride this morning. We just moved to Florida, and I was thinking about how many surveying measurements have been done to determine the average elevation (~100 ft in FL). I'm sure that's determined by surveying. Is that correct? How many surveys do you think it would take to make this kind of estimate?

  • Sabot46290

    The level of detail and equipment needed makes sense as to why I'm not happy having to pay so much to have somebody from my city survey my paltry 1/0th acre lot so we know where to properly place the outbuilding. Thanks for explaining it.

  • Jerry Kitich

    Fun fact: Surveyors don't work in the rain because of the equipment. We (or in my case used to) go hang out in the mall & get paid anyway while we waited to see if it would stop. Or we get sent home & maybe have to take vacation or unpaid time, depending on who we work for.

  • She Devil

    Surveyor: the first to get blamed and the last to get paid (and under paid at that).
    My only advice to homeowners would to be stop whining about the prices of surveys. The reality is that you're receiving a service from a licensed and insured professional that takes a fair amount of man hours to complete at the very least. It's like people are under the impression surveyors just take a couple of pictures, place some pins, and that's that.. Magically a survey appears. "How could that be any more than $100?! I got a survey 30 years ago for $75, i swear!"

  • diamine665

    I should've seen this before my summer job at the surveying department. Oh well, your fault for being a decade late.

  • ToomanyJ's ToomanyR's

    🤷‍♂️🤷‍♂️🤷‍♂️🤷‍♂️🤷‍♂️🤷‍♂️🤷‍♂️🤷‍♂️🤷‍♂️
    Simple and still went over my head.

  • derie ranzoal

    hi there, wondering how water level doesn't lie and do tell the truth that water level does not curve at all, right?

  • fnam lnam

    hey bro NOT how you did the survey/levelling . . . remember your teaching a NOVICE who knows nothing on engg . . .

  • Gary Mechtec

    clicked on this tube , thought it was going to go through the process of land boundaries. setting up gear, working with known pin locations and surveying home owners land property lines.

  • stevebrannon69

    When you think about it, surveyors are flat earth advocates, because land surveys and legal descriptions are done on the horizontal.

  • Shivam Gupta

    A Transit Theodolite with a stadia diaphragm and an anallatic lens can easily measure horizontal distances by using formula D=100s where s is the difference between upper stadia and lower stadia

  • Julio Aguilar

    “Hey, I just wanna waste 10 mins of your hard work to ask something I already know but… what are you doing??” We’ll sir, we gonna build a highway across your property and this is a DOT job so you’re fucked. That’s my life every day now 😂😂😂

  • Black Viper

    First time I saw engineer using this equipment I went straight and asked hey! what video you shooting. 🤣🤣🤣🤣

  • MR ENGINEER

    I really had a nice time 2 summers ago when I worked part-time assisting a Surveyor at a construction site. I enjoyed working with the Theodolite and other measuring equipment. 24 months later, the $12 million apartment project is over and wow, I am so happy to have made my contribution. And it's the largest project I have worked on. Hoping for more to come. #HappyEngineering #HappySurveying.

  • Col. Cotton Hill

    This is great. My dad is a retired land surveyor. I used to help him during my teens and 20s. Now i am looking to become a surveyor myself!

  • vasant sande

    As a lifetime civil engineer who did surveying in the mornings and engineering in the afternoons, demonstration
    shows surveying simple, it ain't, better talk to regional county surveyor and follow his advice. Love all surveyors
    and civil engineers out there.

  • Ryan Subbu

    I have done lot of survey work with Wild T1,Wild T2 and Lieca total,stations from Dubai dry dock and Qatar LNG storage tank setting out jobs. I Worley close to 2 mm accuracy in setting out Tank alignment and other important aspects of the shell tank .
    It so refreshing to watch your videos.
    You are touching all aspects of civil engineering. Waiting for some on thermodynamics and heat engines

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