Horizontal position representation is a way of showing where things are located in a picture. Imagine you draw a picture of your room on a piece of paper. You can see everything in your room from the front of the piece of paper, right? But how do you show where everything is located in the room?
One way is to use horizontal position representation. You can draw a line across the bottom of the paper representing the floor of your room. Then, you can draw vertical lines representing the walls of your room, starting from the bottom line and going up.
Now, let's say you want to show where your bed is located in the room. You can draw a little rectangle or square on the paper, and then draw a smaller, vertical line inside the rectangle, to show that the bed is standing up. Then, you can draw a little dot or x inside the rectangle to show where on the floor the bed is located.
You can do this for all the things in your room - the dresser, the windows, the door, etc. This way, anyone looking at your picture can tell where everything is located in your room.
So, horizontal position representation is like drawing a map to show where things are located in a picture. It can be helpful when you want to explain something to someone, or when you want to make sure you remember where things are located in a picture.