source: orange/docs/widgets/rst/classify/classificationtreeviewer.rst @ 11404:1a7b773d7c7b

Revision 11404:1a7b773d7c7b, 2.3 KB checked in by Ales Erjavec <ales.erjavec@…>, 13 months ago (diff)

Replaced the use of :code: role with :obj:

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1.. _Classification Tree Viewer:
2
3Classification Tree Viewer
4==========================
5
6.. image:: ../icons/ClassificationTreeViewer.png
7
8A hierarchical browser for classification trees
9
10Signals
11-------
12
13Inputs:
14
15
16   - Classification Tree (orange.TreeClassifier)
17      A classification tree
18
19
20Outputs:
21
22   - Examples (orange.ExampleTable)
23      Examples from the selected tree node.
24
25
26Signal :obj:`Classified Examples` sends data only if some tree node is
27selected and contains some examples.
28
29Description
30-----------
31
32The widget shows the tree as a hierarchy in a textual form. Although less
33fancy than the graphical viewer, much more information fits in a Tree Viewer's
34window than in the graphical viewer's one.
35
36.. image:: images/ClassificationTreeViewer.png
37   :alt: Classification Tree Viewer widget
38
39The widget's options allow choosing the columns to be displayed, setting the
40general depth of the display (individual nodes can, of course, be opened and
41closed manually).
42
43On the right hand side there is the tree, where it is possible to select a
44single node. The rule describing the particular node is shown at the bottom,
45and the training examples belonging to the node are put on the output.
46
47
48Examples
49--------
50
51The obvious use for the widget browsing the induced tree. Orange Canvas,
52however, offers something more exciting: the widget can be used for exploring
53the examples belonging to a certain node through using any other widget.
54If you are a beginner: this widget's output behaves exactly like the output
55of the file widget, with the exception that instead of reading the examples
56from a file, it gets them from the tree.
57
58.. image:: images/ClassificationTreeViewer-Schema.png
59   :alt: A schema with Classification Tree Viewer
60
61In the above example we constructed a tree from the Wisconsin breast cancer
62data. We explore the tree nodes by feeding the examples in the Data Table,
63by checking the attribute value distributions for each node and
64seeing where the examples lie in the Scatter plot. To make the latter more
65informative, the Scatter plot shows the entire data set (examples from the
66File Widget), but marking - by plotting solid symbols instead of hollow ones
67- the examples belonging to the particular tree node, as shown in the
68snapshot below.
69
70.. image:: images/ClassificationTreeViewer-Example-S.png
71   :alt: Scatter plot showing the examples from a particular tree node
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