====== 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:
decision_tree
###
number_of_classes
classes_names#
number_of_features
features_names
###
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:
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
###
Now you know how to create your own decision tree 'by hand'!
[[geodma:manual_02|Go back to the manual.]]