Surfaces can be represented by models built from regularly or irregularly spaced sample points on the surface. See also surface model . Because a surface contains an infinite number of points, some subset of points must be used to represent the surface. Each model contains a formalized data structure, rules, and x,y,z point measurements that can be used to represent a surface. A graphic pattern used to represent a feature.
Many characteristics define symbols, including color, size, angle, and pattern.
See also text symbol , marker symbol , shade symbol , and line symbol .