Mind mapping, the practice of visually representing linked ideas in diagrams, is a controversial technique. Some people find mind mapping's branching trees and multiple colors to be a distraction from the main task of organizing ideas. Proponents counter that the resulting diagrams are concise, quick, and reveal patterns you might otherwise miss. Either way, GNU/Linux offers a number of such programs from which to choose. The most useful ones I've encountered are kdissert (now Semantik, although the Debian repositories haven't caught up with the name change) and VYM (View Your Mind). Both offer a powerful graphical interface, and both extend the concept of mind mapping by allowing you to attach text and graphics to a diagram and by supporting filters to export results into forms usable with other programs.
As you might expect, the editing windows of both programs center on the mind map. In kdissert, buttons are scattered on each side of the window: basic commands on top, the button for a file manager-like view of the mind map on the left, customizing buttons on the right, and toggle buttons for attaching text and images on the bottom. By contrast, VYM crowds all buttons into two rows on the top. These approaches can be equally annoying, with the scattered buttons leaving you uncertain where to find a feature, and the two rows making for a formidable array in which to locate the right button.
Creating mind maps
Both programs start from a central point from which you can add branches and sub-branches as ideas occur to you. The result looks formal in kdissert, with branches displayed as straight lines and the name of each branch appearing in a box. VYM opts for a more sketchy look, with tapering, often curved branches with unboxed names at their end.
In kdissert, you can order the branches for export to another document format, a feature that can also be used to prioritize branches without rearranging their order. You can also reorganize branches so that they are grouped equidistant around the starting point in kdissert.
If necessary, you can reposition an entire mind map in either program by dragging the starting point to a new position. However, since in each program the work area has no fixed dimension, technically, repositioning is unnecessary.
In both kdissert and VYM, you can add new branches to the map from the right-click menu, and drag branches around as needed. VYM has drag and drop support that kdissert lacks -- for instance, you can attach a sub-branch to another branch simply by dragging it -- but, if you take the effort to learn its key commands, kdissert is just as convenient. As maps in either program grow more complex, you can scroll through the window or change the zoom level to see other sections.
Using either program, you can color-code branches to add another dimension of meaning, or attach icons to add to the information conveyed. For instance, in kdissert, you can add icons to a branch as a warning, or to mark a good idea, or places where you need to do more work or clarify. Similarly, VYM includes markers to set the priority, evaluate ideas, and to indicate approval or disapproval according to several different systems. However, these markers have the usual weaknesses of icons, in that their meaning is not always immediately apparent from the graphic, and they can be hard to decipher at a smaller size -- both of which tend to defeat the intent of adding extra meaning. The feature might be more useful if you could define your own system, but neither program allows you to do that.
VYM gives you the option of selecting the thickness of each branch to indicate its importance. Unlike the color coding or icons, this feature has the advantage of being identifiable at a glance.
Adding text and graphics
In VYM, you can title branches by clicking on them in the main editing window. To add text to a branch, you select it, then add the text in RTF format in a separate editing window. Given the ability to edit other aspects of the mind map directly in the main window in VYM, this organization seems unwarranted, although it does have the advantage of allowing a few more formatting options for the text.
However, kdissert is equally clumsy with text. In kdissert, titles and text alike are attached to a branch in a sub-window that you can toggle open and shut at the bottom of the main editing window. In both programs, the advantage of adding text is lessened by the fact that, to view it, you have to select a branch in the editing window, then open the window or sub-window to see if any text is associated with it.
Kdissert handles graphics with more sophistication, showing a thumbnail on the branch and a slightly larger one in the formal tree pane on the left side of the editing window. You can also add a caption to an image in kdissert. In VYM, although you can drag and drop images into the mind map, they are either hidden or displayed at the end of a thin black sub-branch, often making them even clumsier than text to work with.
Exporting mind maps
Once you have completed a mind map, both kdissert and VYM give you the option of saving it in their native formats. In kdissert, you can also export a mind map as a .PNG file, while in VYM, you can choose other common graphic formats, such as .JPEG and .BMP.
If your mind map is meant as an outline for a presentation or article, you can save time in both programs by exporting it into a format readable by the program that you will be writing in. Both VYM and kdisserct include support for HTML, LaTeX, XML, and OpenOffice.org, although VYM exports only to OpenDocument's presentation format and uses one of the two uninspiring templates that are bundled with OpenOffice.org, while kdissert, despite the advantage of exporting to either presentation or word processing formats, has trouble positioning some graphics and uses OpenOffice.org 1.x format. Export to a markup language may be a better choice in both programs.
Both VYM and kdissert take advantage of the possibilities allowed by moving from a sheet of scrap paper to a computer screen to extend the concept of mind mapping. However, their additional features have mixed results. You might wonder if the added features simply amount to distractions, tempting you to worry over colors or fonts when you should be focusing on ideas or organization.
Another possibly distraction in both programs may be learning to add branches and navigate quickly, although VYM's drag and drop support makes it slightly quicker to learn than kdissert. This distraction should disappear as you become more comfortable in either program.
For those who find mind mapping an aid to creativity, both kdissert (or Semantik) and VYM are well worth investigating. You may just find that making the move from paper to computer adds new dimensions to the old concept of mind mapping.