The first pixel position, the second pixel position, and so forth.

As we move from the top of the screen or

the top of the image down, we move up once again in pixel position.

So the first row, the second row,

the third row or you can view these as rows and columns as I was saying.

So this is what we might consider an integer-based coordinate

system where there is no in between, you're on 1 or you're on 2 or

you're on 3, there's no halfway between 1 and 2, for example.

You might also call this device specific, so it maps very clearly to your display.

On the right hand side of the screen is a 2D Cartesian coordinate system.

This is a type of coordinate system that you might have experienced before in

a math class like geometry where we've got the 0,

0 position at the origin or in the middle.

And as you go up, you go into the positive y direction.

As you go to the right, you go into the positive x direction, and

we also have negatives.

So you can go below the origin which would be the negative y direction and

you can go to the left of the origin which would be the negative x direction.

This is real based or a floating point based number system.

So that between 0 and

1 for example there's actually an infinite number of positions.

So you can go to 0.5, you can go to 0.55, you can go to 0.5555, and so forth.

So there's an infinite number of mathematical points between any two

points, unlike the 2D Bitmap coordinate system that we just spoke of a minute ago.

In this coordinate system rather than talking about pixels,

we're often talking about a unit of measurement.

So one might mean one meter, like it does in Unity or

it could be one mile or it could be one inch, or one centimeter.

But like I said in Unity, we typically work in meters as our unit of measurement.