How does land surveying work?

Summary

This video explores the importance of land surveying in civil engineering projects, highlighting the history and evolution of the profession. Grady explains how surveyors use tools like theodolites, total stations, and even DIY methods like sight levels, water levels, and laser levels to measure angles and elevations for large-scale projects such as roads and bridges. The video also offers a simple tutorial for conducting a topographic survey at home. Sponsored by Blue Apron, Grady shares the convenience of meal delivery services while working on home improvement projects.

Takeaways

• 📏 Surveying is essential for large-scale projects like roads, bridges, and pipelines.
• 🏛 Civil engineering projects often begin with a land survey to establish boundaries and assess land features.
• 📐 Surveying is the science of taking large measurements and determining the topography and layout of land.
• 🔭 A common surveying tool is the theodolite, which measures angles between points and helps in triangulating locations.
• 📡 Modern theodolites, called total stations, can measure both angles and distances, equipped with on-board computers.
• 📜 Surveying has a rich history and was used for ancient constructions and mapping, like the Great Trigonometrical Survey of India.
• 🌍 Surveying has advanced with technologies like GPS and unmanned aircraft for more complex projects.
• 🔧 There are DIY surveying methods like using a sight level, water level, or a laser level to measure relative elevations.
• 🎯 The laser level is a fast and accurate tool for home surveys, useful for topographical measurements.
• 🛠 Surveying combines legal knowledge, technical skill, and fieldwork, making it vital to civil engineering projects.

Q & A

What is the main focus of the video?

The video focuses on the importance of land surveying in civil engineering projects and demonstrates some basic methods for performing a topographic survey at home.

What types of projects typically require surveying?

Surveying is typically required for large projects such as roads, bridges, dams, pipelines, and any civil engineering projects that involve land measurement.

Why is surveying important in civil engineering?

Surveying is essential in civil engineering because it helps determine legal boundaries, locate existing infrastructure, and measure the topography and slopes of the land, which are critical for construction projects.

What is a theodolite, and how does it work?

A theodolite is a tool used in surveying to measure angles between two points. By combining these angles with distance measurements, surveyors can triangulate the location of any point using trigonometry.

What are total stations, and how do they improve upon traditional theodolites?

Total stations are modern theodolites that not only measure angles but also distances. They have onboard computers to perform calculations and record data, making surveying more efficient and accurate.

What basic surveying tools were demonstrated in the video?

The video demonstrated a sight level, a water level, and a laser level as basic tools that can be used for a DIY topographic survey at home.

How does a sight level work in a survey?

A sight level combines a telescope and a spirit level. By sighting a surveying rod and centering the bubble, you can determine a point that is level with your eyeline, allowing for simple elevation measurements.

What are the advantages of using a water level for surveying?

A water level is inexpensive and doesn't require a line of sight, making it useful for measuring around obstacles like trees or corners.

Why is a laser level considered the best option for a DIY survey?

A laser level is fast and efficient for creating a perfect horizontal line, allowing for quick and accurate measurements. It is a popular tool for both professional and DIY projects.

Why is surveying considered one of the oldest and most important careers?

Surveying is one of the oldest careers because of its historical role in building ancient structures and creating accurate maps. It remains crucial because land ownership and construction rely on precise measurements.

Outlines

00:00

📏 Introduction to Surveying and Measuring Tools

This paragraph introduces the use of everyday measuring tools such as rulers and tape measures, noting their limitations for large-scale projects like roads or bridges. It then transitions to the main topic of the video: land surveying, a crucial aspect of civil engineering, and how viewers can try simple surveying at home. The paragraph also briefly touches on the role of surveyors in determining property boundaries and topography, and mentions the historical significance of surveying in major construction projects like the Great Trigonometrical Survey of India.

05:02

🔭 Theodolites and Modern Surveying Equipment

The focus here is on the tools of the trade for surveyors, primarily the theodolite, which measures angles between two points. The modern version, called a total station, includes the ability to measure distances and perform calculations using onboard computers. The paragraph explains how surveyors use this equipment in conjunction with reflectors to measure points with precision. It also introduces more advanced technologies such as GPS and unmanned aircraft, while emphasizing that surveying technology has evolved significantly but retains its fundamental importance.

🏡 DIY Surveying Methods for Home Projects

This paragraph presents three methods of DIY surveying: a sight level, a water level, and a laser level. Each method is explained in detail, highlighting the advantages, disadvantages, and use cases for performing simple topographic surveys. For example, the sight level requires a helper and is less precise, while the water level allows measurements around obstacles like trees. The laser level, although more expensive, is quick and effective. The paragraph underscores the practicality and simplicity of these methods for small-scale home improvement projects.

🌍 The Importance of Surveying as a Career

The paragraph explains why surveying is such an important profession, linking its significance to the value of land ownership. It highlights the combination of legal, technical, and fieldwork skills required for a career in surveying, emphasizing the surveyor's role in civil engineering projects. The paragraph concludes by recognizing surveying as a mix of ancient tradition and modern-day necessity.

🍽 Blue Apron Sponsorship and Final Thoughts

The video concludes with a sponsorship message from Blue Apron, where the host shares his personal experience with their meal delivery service. He praises the convenience of Blue Apron, especially while settling into a new home. The paragraph includes a promotional offer for viewers, encouraging them to try the service by providing a discount code for three free meals. It wraps up with a final thank you and call for viewer feedback.

Keywords

💡Surveying

Surveying is the science of taking large measurements, particularly for civil engineering projects like roads, bridges, and pipelines. It involves determining legal boundaries, mapping topography, and aligning infrastructure. In the video, surveying is described as a crucial part of any large-scale construction project.

💡Theodolite

A theodolite is a tool used by surveyors to measure angles between points. It combines angle measurements with distances to triangulate the location of points using trigonometry. Modern versions, called total stations, are equipped with computers to record data. The video describes it as a core tool in surveying.

💡Topographic Survey

A topographic survey is a process used to map the elevation and contours of land. This is essential in planning civil projects to ensure that construction considers the natural terrain. In the video, the presenter performs a simple topographic survey of his yard to understand the land’s relative heights.

💡Datum

A datum is a reference point in surveying from which measurements are made. It serves as the baseline height to compare elevations in a topographic survey. In the video, the presenter explains how he selects a datum point to measure the relative heights of his yard’s grid points.

💡Total Station

A total station is an advanced theodolite that can measure both angles and distances, using onboard computers to calculate and store data. The video highlights how this modern equipment simplifies surveying by automating many of the necessary calculations.

💡Leveling Survey

A leveling survey is a method of determining the difference in height between two or more points on land. It is useful in understanding land slope and drainage issues. The video’s focus on home surveying includes using simple tools to perform a leveling survey in a backyard.

💡Triangulation

Triangulation is the process of determining the location of a point by measuring angles from known points at either end of a fixed baseline. This technique is fundamental in surveying for mapping and layout projects. The video references it in the context of using a theodolite for surveying.

💡Water Level

A water level is a simple surveying tool consisting of a clear tube filled with liquid, used to measure elevation differences. The water naturally levels itself at both ends, allowing for measurements without needing a line of sight. The video demonstrates how this tool can be used for DIY surveys.

💡Laser Level

A laser level emits a perfectly straight beam of light that creates a horizontal reference line for leveling tasks. It can be used to align structures or measure elevations in a survey. The presenter in the video describes how he uses a laser level for accurate, quick measurements in his yard survey.

💡Civil Engineering

Civil engineering involves designing and constructing infrastructure like roads, bridges, and buildings. Surveying plays a key role in these projects by providing the precise measurements needed for planning and construction. The video emphasizes the partnership between surveyors and civil engineers to ensure project success.

Highlights

Surveying is the science of taking big measurements, essential for civil engineering projects.

Surveyors are responsible for determining legal boundaries, existing infrastructure, and land topography.

Surveying has a rich history, playing a role in major ancient constructions and mapping continents like the Great Trigonometrical Survey of India.

A theodolite is the ubiquitous tool of surveyors, measuring angles between points to triangulate locations using trigonometry.

Modern theodolites, called total stations, can measure both angles and distances, and come equipped with on-board computers for calculations.

GPS and unmanned aircraft have advanced surveying techniques, allowing for more complicated projects.

The video demonstrates how to perform a simple leveling survey at home using basic and inexpensive tools.

A sight level, a combination of a telescope and spirit level, can be used for a basic leveling survey, though it lacks precision.

The water level method, using a clear vinyl tube filled with liquid, is an inexpensive and effective way to measure levels without line of sight.

A laser level offers the fastest and most efficient way to perform a leveling survey, especially for DIY projects.

Surveying remains one of the oldest and most important careers due to the value of land and its importance in civil engineering.

Land ownership is often a person’s most valuable asset, making accurate surveying critical.

Surveying combines legal knowledge, fieldwork, and technical challenges, making it a dynamic and essential career in civil engineering.

Blue Apron sponsors the video, offering a service that delivers fresh ingredients and recipes directly to consumers’ homes.

The video encourages viewers to try DIY surveying techniques and appreciate the historical and practical significance of the profession.

Transcripts

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.

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Again, thanks for watching, and let me know what you think!