Unlike a bitmap, which is an image produced by a fixed matrix of colored pixels like a mosaic, a procedural map is generated by a mathematical algorithm. Consequently, the types of controls you might find for a procedural map will vary depending on the capabilities of the procedure.

Three procedural maps (bricks, Perlin marble, and splat), with variations

A procedural map can be generated in two dimensions, or in three. For example, Wood has a grain that goes through the assigned geometry. If you cut away part of an object with wood assigned as its texture, the grain in the cutaway portion matches the grain on the object's exterior: it is all generated by the same procedure.