And welcome to Jews, as in the previous video, we had to watch it ellipsoid side Hengdian.
And how are these things estimating the shape and size of the Earth when we are working in three dimensions?
And now let's look at how that represented inside map.
It's unfortunate that in places our map will, as well as conflict, the the data stored and the way
the data is displayed.
So to make that, we can separate those out because conceptually they are very separate things.
As you can see, the map is open now.
Good.
And they die and then click on the ballot box is displayed in this dialog box, but also the location
and then select the country, play and choose.
And within the dialogue box is closed and the shapefile is added in the data view area.
What assumptions they made about the shape and size of the Earth.
When the data is collected, it is very important to think and to consider, because if we don't think
about that, we can have major impact on the accuracy of your analysis.
Now let's go to table of contents and select play and then right click on the edge of Light is displayed
from the playout select property option in their properties dialog box source that Chozen is displayed.
So here in this source that it does give some basic information about the size and the shape of the
Earth.
Then this data was created and we see this and this time geographic coordinates system that is this
is the bloodiest nineteen eighty four.
This is just the iceberg.
Every region of geographic coordinates system and the images in this case, thenceforward geodetic survey
and this is the word geodetic survey of nineteen eighty four, of course periodically the update and
receive our survey for our planet and our estimation of the size and shape in order to be able to get
better coordinates.
And that is why if somebody decided that some particular location point is at 35 degrees or not, and
if that's not enough for you to be able to place that one because you do not know what assumptions about
the size and the shape of the earth are being made, then that measurement was taken.
This is very important because figure somebody just gives you latitude and longitude.
That's not enough.
We need that other information about those assumptions, the size and the shape of the earth.
So this is telling us that the point of the latitude and longitude that I'm making of this, why they
all are connected to make the country fly here.
They all are connected, according to WTS nineteen eighty four, there's a very popular system for this
data and collecting data from across the world.
In fact, the Global Positioning System uses WGAN nineteen eighty four, but they were maybe the latitude
and longitude.
You could go to a lot of debate about understanding what assumptions that WTS nineteen eighty four is
making.
You probably should, but for right now it's enough to know that this particular year data for all of
the points and all of the geometries and all of its nine then be the likely position as long as we understand
that it is in the context of all of its assumptions of the Macías nineteen eighty four.
Now let me close this dialog box.
Next, we have another thing that we should know.
Go over to the table of content and right.
Click on the I apply.
It is displayed from this layout just properties option, the data free properties dialog box with coordinate
system that Joelson is displayed that we can see to imagine folders that the Ojai's has lost its geographic
coordinates system and the second is projected gone into the system.
And this is one of the places where Arkes gets terminology somewhat confused and we start to get that
conflict between the assumptions and the size and the shape of the Earth and how we display the data
through this prediction.
And one of the reasons that we start to get the confusion is because I just got bored of this X coordinate
systems.
So as we can see.
We have the first Dobrowski coordinate system and the second is projected coordinate system.
I want to continue to talk about this WALDOR coordinate system now, expand geography, coordinate system.
So here you can notice all the places around the planet and then there is one expert.
So it just expand and scrolling down and we see the biggest nineteen eighty four effort as a whole bunch
more.
These are basically of the different service, datums joy, ellipsoid, all of that that and understands
by displaying data.
So it's very good that the occupiers understand why.
Geodetic survey of nineteen eighty four because I said so much including the cheapest satellite uses
W.G. is nineteen eighty four to record its coordinates, but far from only that system that we might
have.
So we do have other water geodetic survey that this WTS 1972 and WTS 1976 and many more as you can see
in all bunches given.
So you might end up with a different status that uses different sets of assumptions.
And what's very important here is to make sure that this ping matches naturally.
This does not really have to integrate all of this data.
And any time automatically you have to know what you are doing, because if we end up with different
set that I'm using in different sets of assumptions about the size and the shape of the Earth, it will
even try to overlay something about a completely different way and not able to do this conversion.
But I also want to show you over here, we have a whole bunch of different coordinate locations like
that have been Asia, Africa, South America and many more now.
Expen.
Europe, although you can see in Estonia and then here we have Canadian data.
Nineteen seventy two.
They have all this different system here specifying locations on the planet.
The looks of a big selvi is a system for specifying latitude and longitude according to an entire planet,
to try to come up with the size and the shape of ah, it is pretty good across the entire planet for
giving the latitude and longitude coordinates.
But that is the case that in different situations, if we are not worried about mapping across the entire
planet, maybe you are worried about what we saw in Estonia or maybe any individual places.
You may not care about trying to approximate the of the entire planet enough to coordinate over.
And so I want to come up with the models of the size and the shape of the entire earth, but a part
of the earth that I am mapping and see I'm mapping for a particular country.
And so we may do this to make a sophisticated model for giving accurate latitude and longitude as long
as we are within this area.
So like we were looking at Estonian system here, maybe if we are working with this data or we are mapping
in Estonia, we might want to use those if it is very accurate for that area using a set of assumptions
that closely approximate the surface of the earth in Estonia.
So what we may do if we are working with some particular region, it may be a fantastic idea not to
use some kind of one wide system.
But they use this system that was designed for mapping your area because that's going to provide us
much more accurate coordinates within that area as long as we are outside and use it for something that
you are not intended for, but also and understand all this different distance.
So if we end up downloading data of some places and we need the data of some other place, it could
be one of those regional systems, which I guess an understanding, but it will not automatically convert
it if we understand it.
But we need to do the conversion.
For example, if you've got some data of Luxembourg 1930 and you.
Like trying to integrate within some European water like that is using German European data, both like
that, you'll need to convert those one system are like one system to the other system in order to make
sure that it aligns most accurately because our clients does not just do that for you that understands
this, but that does not mean that you just throw a bunch of data which uses a bunch of different systems
in your project and get them to correctly align because they do not have to start to get position editors.
And basically what I want you to understand is this geography coordinates system folder is all about
assumptions of the size and the shape of the planet when we are collecting data and this folder projection
coordinates system folder is really what we call a projection in geography.
This is what we are going to display in that data.
And this is very important coordinate system.
This is about how we are going to all that data.
And this is about how we are going to display that data in map format that is in two dimensional.
So then we are talking about just the values they should have gotten, the information that comes out
of this geography coordinate system folder, because that's how we are going to know what sort of assumption
was used when the data was collected so that they would be able to back that with a particular projection
when we want to display it in that climate.
I hope you like the video stadion.