In linear perspective there is a horizon line and a vanishing point to which all non horizontal lines lead to. There are also vertical lines. Proportion lines are simply a starting point for an artist to determine the correct proportions of the portrait or picture.
The origin
It is called the origin, or the point (0, 0).
No. You have four corners, each with an odd number of lines going out. Each of these must either bee the starting point or the ending point, but you can only have one starting point and one ending point.
Very simply (and unimaginatively), the horizontal axis or x axis and the vertical or y axis.
In linear perspective there is a horizon line and a vanishing point to which all non horizontal lines lead to. There are also vertical lines. Proportion lines are simply a starting point for an artist to determine the correct proportions of the portrait or picture.
The origin
vanishing point
A horizontal ray in math is a line that runs horizontally that has one starting point and goes on forever in the opposite direction.
The starting point for elevation is typically referred to as the base or ground level. This is the point from which the measurement of elevation or height above sea level begins.
It is called the origin, or the point (0, 0).
The base of a wave is the lowest point of the wave where it meets the horizontal axis. It represents the starting point of the wave's oscillation.
No. You have four corners, each with an odd number of lines going out. Each of these must either bee the starting point or the ending point, but you can only have one starting point and one ending point.
The North and South Poles.
The origin of latitude measurement is the equator.
Very simply (and unimaginatively), the horizontal axis or x axis and the vertical or y axis.
The starting point would be the equator. Lines of latitude run parallel to the equator.