Geomantics - 3D, GIS, Landscape Visualization, Graphics and Business Software     
Geomantics site front page

Using Ecology Layers
GenesisIV's Ecology layers add vegetation to landscapes using a straightforward ecology model based on altitude, aspect and slope. Ecology layers are most useful for Educational and Artistic projects where precise placement is less important than with GIS work, and offer a useful shortcut.


In this tutorial we'll use a slightly modified version of the default landscape to which we've added another hill and a small depression.

We'll render the image from above, using the default fractal colours. This isn't intended to be photorealistic, rather to show how the distribution of vegetation is applied.

  
 

For this example we'll use a single ecology layer, which we'll link to the red Palm plant. This ensures that our effects are highly visible. We've also set the size and density of the Palm to be quite high.

Our first example just places the trees using Altitude only. By setting the slope to 0.5 with a tolerance of 0.5 (so range 0.0 - 1.0) and Aspect at 180° with a tolerance of 180° (so a range of 0 - 360) these have no effect on the distribution.

 

  

Rendering at Fractal Level 2 draws the trees. Because we specified an altitude of 0.5 (i.e. half way between minimum and maximum landscape height) with a tolerance of 0.2 trees are placed at random on any terrain between 30% and 70% of maximum height.

The very dense placement we've chosen produces a well defined band. Lower densities would produce a more natural effect.

  
 

Using slope is similar to altitude, but the effects tend to be less easy to predict. Using the preview button generates a thumbnail of the distribution before rendering.

Here we've set the Altitude distribution to have no effect and are placing vegetation around a mid-range slope. Note that we use relative slope, where the range 0 .0 (flattest) to 1.0 (steepest) covers the range of slopes in the landscape, as this is more intuitive to understand.

  
The results of our slope distribution shows circular patterns around the hills.  
 

Aspect is the angle the terrain is sloped towards. An aspect of 0° indicates the terrain slopes in a northly direction, with 90° east, 180° south and 270° west.

For the next example we've set the distribution to be by aspect only, between 170° and 190°.

 
The result shows a quite clear distribution on south facing slopes.  
 
Finally, we'll combine all three parameters to produce a more realistic looking forest. In this case we've set our distribution so that Palms will appear on south facing slopes, at a middle altitudes and just below, where there is a gentle to medium slope.  

Our final image shows the effects of this combination.

Multiple ecology layers can be combined to give more complex effects.