An overview

Geomorph is a height field generator and editor for the Linux operating system.

A height field is a kind of topographic map.  It is a 2D projection of a 3D landscape.

Geomorph generates square images and shows a 3D preview of the resulting landscape.  The resulting 2D image can be processed with a tool like Povray for rendering the landscape.

Height field	Preview	Povray rendering

See also the Gallery.  Povray scenes used in the author's part of the gallery are included in the Geomorph package.

Geomorph actually exists in an alpha stage, localized in French, English and German. Here are some screenshots. It is generally stable.

Its main features are, for now:

• An environment allowing multiple documents in multiple windows.
• Output in PNG files with 16 bits per channel, from 128x128 to 4096x4096 pixels, giving 65536 levels from black to white.
  
• Tools to generate height fields by simple subdivision or repeated sum of an arbitrary surface.
• A fractal pen for drawing irregular surfaces.
  
• Pens for drawing smooth strokes, craters, faults, cracks and fissures.
• Edit and transform tools appropriate to image editing - brightness/contrast and the like (few "paint" programs can edit 16 bits per channel images).
• Edit and transform tools relevant to height field editing - erosion, quantization ("terraces"), cityscapes, and the like.
• A Povray run button, for testing the current image with a scene you select.
• An undo/redo history, with multiple levels. The default history stacks has 5 levels, but this parameter can be adjusted in the configuration file.
• A display scale control.
• An OpenGL preview (MesaGL).
• A tool for editing configuration files, where default directories and other parameters are saved.

The Geomorph documentation is mainly made up of the tutorials and the guides of this web site.

Geomorph creates height fields by distorting a surface in a random way. Distortions are applied at progressively decreasing scale levels.

Suppose that we start from a flat surface of 512x512 pixels. In a first step, the surface center is moved vertically with a randomly chosen altitude, a bit like pinching a sheet. In a second step, the surface is divided in four parts, and the center of each part is also moved randomly above or under its current level. In a third step, each of this four parts is also divided in four, for a total of sixteen surfaces, which are then pinched in their middle, and so on until the subdivided surfaces have a 3 pixel diameter or less.

A slice taken in the whole surface would roughly have this look:

Step 1	Step 2	Step 3	Step 4

Usually, unlike this example, the surface is smoothed at each step (much more like the pinching of the sheet).

This subdivision method is not unique to Geomorph, it is frequently used for generating artificial height maps. Applying the same process at progressively decreasing scales gives a so-called "self-similar" surface. This surface is characterized by a fractional dimension (or fractal), which means, in this case, a dimension between 2 and 3.

Geomorph also provides a variation on this process, in which surfaces are added to a base surface at progressively decreasing scales. The added surfaces are derivated from a primitive surface, usually a gaussian bell, or from any image chosen by the user.

Geomorph is an answer to my own creative requirements under Linux, for aesthetical purposes. The available tools when I decided to work on this project (at the end of 2000, I think) were lacking functionnalities or stability.

I am in part motivated by an interest towards the biosphere and the processes which make it evolve. This is somehow for me an extension of photography.

Developing software is also a self-actualizing activity of creation.

I think we are still in the infancy of art creation by digital means. It is still possible, and sometimes required, to develop our own tools. This is not unlike the Middle-Age or Renaissance painters who prepared their pigments themselves.

A road map?

I already have a lot of ideas waiting to be implemented. These ideas are answers to specific requirements for landscapes creation. Here are some of them, in a jumble (without any promise!):

• Tools for importing and scaling external images or height fields.
  
• A generator and editor for tree-like structures, for creating cracks, eroded crests or river deltas.
• A "route" pen, working with a function for animating the camera.
• Selection masks, or the like.
• Better erosion tools (for digging rivers in an existing height fields, for creating terrains with rounded crests, and so on).
  
• Tools for assisting in the creation of Povray scenes, for instance a GUI for choosing the main parts of a landscape (sky, clouds, ground, sun, textures, water plane).
  

Contact:    Patrice St-Gelais