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**