The term "visualization" has become a hot topic GIS during the last several years. More realistic 3D renderings of landscape elements
will form snapshots of analysis results, providing a glimpse of aesthetic as well as environmental and economic concerns.

1. 3D terrain generation and rendering
    contouring map --> DEM --> 3D visualization

2. fractal terrain and plant simulation

   What is fractal?
   A rough or fragmented geometric shape that can be subdivided in parts, each of which
    is (at least approximately) a reduced-size copy of the whole.

    Fractal terrain simulation

   Fractal landscapes are often generated using a technique called spatial subdivision. For magical reasons this results in surfaces that are similar in appearance to the
   earths terrain.

   The idea behind spatial subdivision is quite simple. Consider a square on the x-y plane,

     (1) split the square up into a 2x2 grid
     (2) vertically perturb each of the 5 new vertices by a random amount
     (3) repeat this process for each new square decreasing the pertubation each iteration.

  Example:

    Fractal tree generation