====== Creating your Decision Tree 'by hand' ======

GeoDMA creates decision trees automatically. However, you can define a classification by your own. To build your decision tree, you must create an ascii file with **.c45** extension, using, for example, notepad.

This is the file basic structure:

<code>
decision_tree
###
number_of_classes
classes_names#
number_of_features
features_names
###
</code>

where:
  * //decision_tree// is the full decision tree, explained in the above example, with the symbol "#" after each class name (when a leave)
  * //number_of_classes// is the amount of classes present in the decision tree
  * //classes_names// is a list of names, one class per line, with the symbol "#" after each class name
  * //number_of_features// is the amount of features present in the decision tree
  * //features_names// is the list of names, one attribute per line

**Note**: check if //classes_names// and //features_names// match with your created classes and features in GeoDMA to avoid classification errors. The feature names should not have spaces. The classes names can have spaces, however they must **always** be followed by a "#" symbol.





===== Example =====

The following figure shows one decision tree.

{{geodma:example_c45.png?350|}}

The corresponding **.c45** file is shown above:
<code>
Gyrate <= 190.6 -> Small#
Gyrate > 190.6
|  Area <= 182.5 
|  |  Shape <= 2.01 -> Irregular Pattern#
|  |  Shape > 2.01 -> Linear#
|  Area > 182.5 
|  |  Gyrate <= 1227.5 -> Medium#
|  |  Gyrate > 1227.5
|  |  |  Para <= 44.85 -> Large#
|  |  |  Para > 44.85 -> Linear#
###
5
Irregular Pattern#
Large#
Linear#
Medium#
Small#
4
Area
Gyrate
Para
Shape
###
</code>

Now you know how to create your own decision tree 'by hand'!

[[geodma:manual_02|Go back to the manual.]]