Today I'm gonna be showing you how you can perform a survey resection using our handy,
station, I recommend that you watch my last video.
It goes over the important details in setting up the instrument and making sure that it's
leveled in order to capture accurate data and then come back to this video to use the
total station to complete various surveying tasks.
Now in today's video, we're gonna be going over the surveying resection.
A survey resection is occupying a point that you don't know the coordinates to.
This means that there's no northing, easting, or elevations or X, Y and Z coordinates on
the point.
So where your setup is pretty much arbitrary and the instrument doesn't know where to place
itself in the world.
However, if you have points with known locations, you can use these points to calculate where
your instrument is set up.
Remember these points?
The blue, green and orange points?
Yeah, we're going to be using these points to calculate where our total station is located.
Now, while these points may seem familiar, I did, however, make one small modification.
I set these little hubs in the ground.
A hub is a small piece of wood that is driven into the ground to indicate a specific point
and then usually put a mark on it so that there is a specific location to where this
point is on the top of the stake.
I have placed this hub on all of our known points.
That way I am able to specifically pinpoint a location when referring to these colors.
All right, so we have these known points with known coordinates but how does that do any
good for us?
What are we doing with these points to calculate our point?
By occupying the unknown point, we can then resection our location by taking a distance
and an angle between all of these points.
What we're going to do is start out by sighting one point at one specific location.
We will then do something called backsight to the point.
Remember backsighting from leveling?
It's the same concept.
You're zeroing out your location quite literally.
Every time I move the total station, left and right, you can see the angle changes just
slightly.
So we're able to capture to the nearest second the change in our angle.
Once we find the location of where we want to be sighted, we can then set the angle to
zero.
And then any turning we do will reference that angle at zero degrees.
So you're probably wondering, what exactly are we gonna use to sight these points?
Let me introduce you to what we like to call the prism rod.
[♫Music♫] This is a prism and it has a 360 degree reflective
mirror.
When you guys look into this thing you should see the camera lens.
So in video, every time you guys look into this thing at every angle, you're going to
see the camera lens to my camera.
In the real world, every time I look into this with my eyes, I can just see my eyes.
That's because the source of sight, whether it's a camera or your eyes, or -- the total
station, we'll always observe this prism.
Hence the name 360 degree prism.
Now, I also set a new point.
Now this is point unknown.
In the future we'll call this point pink but for now I want to set an unknown point with
an unknown coordinate to then later on verify that our coordinates are accurate.
So what we're gonna be doing is setting up our rod at every single one of these points.
We will then be taking a distance and measure how far away that point is.
With that reading we're also going to measure the angle between this point and the point
previous to it.
Every time we sight a new point, we will then reset our angle to zero to then measure a
new angle to the next point.
[♫Music♫] All right, so here is what we're going to
do.
We're first gonna turn the device on.
The prism that you might be using may or may not use this little device, depending on if
your instrument is robotic or not.
Robotic total stations are self-observant.
They can sight and figure out where sensors are located in space and I don't need to sit
behind the instrument to search and look for my prism every time.
However, for this video I will be behind the total station at all times just to show you
that you can do this with or without robotic.
It doesn't really matter.
The first thing we're gonna do is step on the legs and embed this bipod into the ground.
Go ahead and make sure that this bubble is leveled.
We do that by pressing down on the bipod buttons and maneuvering the rod in a way so that we
finally get the bubble into the middle of the circle.
Okay, perfect.
Now I'm gonna show you how to use this total station to sight points from the prism.
Now the prism is located at a further distance away from our total station.
What we need to do is sight the total station to look directly at the prism and then capture
the location difference between where we're set up and where the prism is located.
To do that you're going to position the total station, point it in the direction of the
rod.
Then you're going to tilt the optics up and down to find the exact location and you look
through the optics to see exactly where the prism is on the rod.
This ring right here allows us to focus our sight so that we can see the rod in the prism
nice and clear.
This little one right here allows us to focus our crosshairs so that we can see where the
center of our scope is at.
The knobs on the side here are fine tuning knobs that make the instrument go left and
right -- and make the scope go up and down.
To take a measurement we simply press the "Record" button.
All right.
Let's go ahead and take our first measurement.
[♫Music♫] Okay, when we look into the total station
here, we're a little bit out of focus.
Let's try to get ourselves into focus.
All right.
That looks good and then we go left and then up -- and it looks like that right there is
the center.
We just have to get close.
You don't have to be perfect.
[♫Music♫] Now we take our first measurement.
[♫Music♫] Okay we now have a reading for our unknown
point to point blue.
Let's take a look at what we got.
So it looks like the distance from our occupation point to the rod is 34.645 feet.
Because this is the first point that we're measuring, the angle is actually going to
be set to zero.
So let's go ahead and do that.
[♫Music♫] Okay, our angle is set to zero.
We have our distance.
We can now record this in our field book.
Let's go ahead and move to the next point.
Okay.
Looks good.
And record.
All right.
So looking here, we can see that from our point of occupation, to the rod, it is 51.150
feet.
Now the angle between point blue and point green is 65 degrees, 36 minutes and 40 seconds.
That's how much we rotated our total station to sight this point.
We will record all this data and then we will go ahead and reset our zero angle to measure
the next point.
All right.
Now we're gonna sight our unknown point.
[♫Music♫] [Dog barks in background]
[Device beeps] Okay and here is what we're reading.
From the location of where we're occupying to our set unknown point, the distance is
36.035.
The angle between point green and this unknown point are 72 degrees, 10 minutes and 42 seconds.
All right, let's go ahead and zero out our angle.
The next position that we have to go to is point orange.
[♫Music♫] And that looks good.
Okay and here we are.
So the distance is 57.445 feet from our occupation to point orange.
The angle between our unknown pink point and orange is 74 degrees, 30 minutes and 20 seconds.
All right, we'll zero this out and we have one more angle and distance to measure.
To complete the resection we have to go back to the first point that we shot in order to
measure the angle between our last point and the initial first one.
So let's go back to point blue.
Bring this into focus.
Go left and go up right there.
Perfect.
[♫Music♫] All right.
We're good.
All right, here is the final measurement.
We see our distance again from the point that we're occupying to point blue.
It's 34.645 feet which matches what we had last time, so that's good.
The angle this time between point orange and point blue is 147 degrees, 42 minutes and
seconds.
If you found this video to be informative please like the video.
If you enjoy surveying content and look forward to seeing more videos, subscribe to my YouTube
channel and with that, I'll see guys next time.
[♫Music♫]