### Aquiring topological information

A root system is represented as a graph object. A root portion is represented as an edge (defined as 2 vertices or nodes) in the graph and is associated to different types of properties e.g. diameter. Recording the whole architecture necessitates a recursive pathway to be followed throughout the root system, with information about each link and segment being recorded at each stage of the measurment.

The recursive pathway is such that always the higher branching order root is measured first (in figure 1 black axes represent the root of order n and the grey axus represent the root of

order n + 1).

In archiroot, 3 basic operations are used to follow the recursive pathway :

* addition of a axis on the same root (<)

* addition of a root of higher branching order (+)

* Exit the current branch when the tip is reached using (FIN / END) in order to return to the mother root where measure was posed.

Shortcuts: F3: end the root (END) Backspace: cancel previous measurment F11: Refresh visualisation F12: Screen capture Ctrl-s: saving the project

**Acquiring position of roots in 3D**

The software must also determine the position of the next node or vertex to be added to the root system. The positions are calculated from the position of the previous node by giving the length and the direction of the new root segment being added (> or +). Two angles are required to determine the direction, namely azimuth and inclination, and the length of the root segment is required to determine the distance to go from the initial position.

**Download **

Before you use the Archiroot software (or visualize the 3D models on this web site), you need to install a VRML viewer. There are several of them. On windows, the Cortona player is excellent and propose various functionalities. The cortona VRML player can be downloaded here

On Linux, you may want to use Octaga player at http://www.octagavs.com/softwarem/octaga-player