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And welcome to Jews, as in the previous video, we had to watch it ellipsoid side Hengdian.

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And how are these things estimating the shape and size of the Earth when we are working in three dimensions?

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And now let's look at how that represented inside map.

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It's unfortunate that in places our map will, as well as conflict, the the data stored and the way

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the data is displayed.

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So to make that, we can separate those out because conceptually they are very separate things.

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As you can see, the map is open now.

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Good.

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And they die and then click on the ballot box is displayed in this dialog box, but also the location

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and then select the country, play and choose.

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And within the dialogue box is closed and the shapefile is added in the data view area.

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What assumptions they made about the shape and size of the Earth.

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When the data is collected, it is very important to think and to consider, because if we don't think

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about that, we can have major impact on the accuracy of your analysis.

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Now let's go to table of contents and select play and then right click on the edge of Light is displayed

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from the playout select property option in their properties dialog box source that Chozen is displayed.

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So here in this source that it does give some basic information about the size and the shape of the

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Earth.

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Then this data was created and we see this and this time geographic coordinates system that is this

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is the bloodiest nineteen eighty four.

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This is just the iceberg.

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Every region of geographic coordinates system and the images in this case, thenceforward geodetic survey

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and this is the word geodetic survey of nineteen eighty four, of course periodically the update and

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receive our survey for our planet and our estimation of the size and shape in order to be able to get

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better coordinates.

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And that is why if somebody decided that some particular location point is at 35 degrees or not, and

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if that's not enough for you to be able to place that one because you do not know what assumptions about

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the size and the shape of the earth are being made, then that measurement was taken.

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This is very important because figure somebody just gives you latitude and longitude.

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That's not enough.

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We need that other information about those assumptions, the size and the shape of the earth.

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So this is telling us that the point of the latitude and longitude that I'm making of this, why they

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all are connected to make the country fly here.

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They all are connected, according to WTS nineteen eighty four, there's a very popular system for this

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data and collecting data from across the world.

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In fact, the Global Positioning System uses WGAN nineteen eighty four, but they were maybe the latitude

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and longitude.

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You could go to a lot of debate about understanding what assumptions that WTS nineteen eighty four is

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making.

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You probably should, but for right now it's enough to know that this particular year data for all of

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the points and all of the geometries and all of its nine then be the likely position as long as we understand

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that it is in the context of all of its assumptions of the Macías nineteen eighty four.

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Now let me close this dialog box.

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Next, we have another thing that we should know.

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Go over to the table of content and right.

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Click on the I apply.

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It is displayed from this layout just properties option, the data free properties dialog box with coordinate

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system that Joelson is displayed that we can see to imagine folders that the Ojai's has lost its geographic

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coordinates system and the second is projected gone into the system.

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And this is one of the places where Arkes gets terminology somewhat confused and we start to get that

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conflict between the assumptions and the size and the shape of the Earth and how we display the data

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through this prediction.

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And one of the reasons that we start to get the confusion is because I just got bored of this X coordinate

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systems.

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So as we can see.

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We have the first Dobrowski coordinate system and the second is projected coordinate system.

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I want to continue to talk about this WALDOR coordinate system now, expand geography, coordinate system.

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So here you can notice all the places around the planet and then there is one expert.

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So it just expand and scrolling down and we see the biggest nineteen eighty four effort as a whole bunch

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more.

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These are basically of the different service, datums joy, ellipsoid, all of that that and understands

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by displaying data.

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So it's very good that the occupiers understand why.

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Geodetic survey of nineteen eighty four because I said so much including the cheapest satellite uses

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W.G. is nineteen eighty four to record its coordinates, but far from only that system that we might

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have.

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So we do have other water geodetic survey that this WTS 1972 and WTS 1976 and many more as you can see

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in all bunches given.

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So you might end up with a different status that uses different sets of assumptions.

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And what's very important here is to make sure that this ping matches naturally.

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This does not really have to integrate all of this data.

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And any time automatically you have to know what you are doing, because if we end up with different

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set that I'm using in different sets of assumptions about the size and the shape of the Earth, it will

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even try to overlay something about a completely different way and not able to do this conversion.

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But I also want to show you over here, we have a whole bunch of different coordinate locations like

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that have been Asia, Africa, South America and many more now.

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Expen.

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Europe, although you can see in Estonia and then here we have Canadian data.

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Nineteen seventy two.

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They have all this different system here specifying locations on the planet.

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The looks of a big selvi is a system for specifying latitude and longitude according to an entire planet,

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to try to come up with the size and the shape of ah, it is pretty good across the entire planet for

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giving the latitude and longitude coordinates.

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But that is the case that in different situations, if we are not worried about mapping across the entire

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planet, maybe you are worried about what we saw in Estonia or maybe any individual places.

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You may not care about trying to approximate the of the entire planet enough to coordinate over.

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And so I want to come up with the models of the size and the shape of the entire earth, but a part

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of the earth that I am mapping and see I'm mapping for a particular country.

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And so we may do this to make a sophisticated model for giving accurate latitude and longitude as long

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as we are within this area.

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So like we were looking at Estonian system here, maybe if we are working with this data or we are mapping

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in Estonia, we might want to use those if it is very accurate for that area using a set of assumptions

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that closely approximate the surface of the earth in Estonia.

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So what we may do if we are working with some particular region, it may be a fantastic idea not to

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use some kind of one wide system.

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But they use this system that was designed for mapping your area because that's going to provide us

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much more accurate coordinates within that area as long as we are outside and use it for something that

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you are not intended for, but also and understand all this different distance.

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So if we end up downloading data of some places and we need the data of some other place, it could

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be one of those regional systems, which I guess an understanding, but it will not automatically convert

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it if we understand it.

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But we need to do the conversion.

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For example, if you've got some data of Luxembourg 1930 and you.

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Like trying to integrate within some European water like that is using German European data, both like

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that, you'll need to convert those one system are like one system to the other system in order to make

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sure that it aligns most accurately because our clients does not just do that for you that understands

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this, but that does not mean that you just throw a bunch of data which uses a bunch of different systems

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in your project and get them to correctly align because they do not have to start to get position editors.

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And basically what I want you to understand is this geography coordinates system folder is all about

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assumptions of the size and the shape of the planet when we are collecting data and this folder projection

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coordinates system folder is really what we call a projection in geography.

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This is what we are going to display in that data.

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And this is very important coordinate system.

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This is about how we are going to all that data.

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And this is about how we are going to display that data in map format that is in two dimensional.

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So then we are talking about just the values they should have gotten, the information that comes out

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of this geography coordinate system folder, because that's how we are going to know what sort of assumption

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was used when the data was collected so that they would be able to back that with a particular projection

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when we want to display it in that climate.

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I hope you like the video stadion.