2-D DVD maps of features
Click 'open table', select 'bird109' and click 'DVD Play/Stop'. You should see and image
like the one presented below:
Only syllable with longer or shorter duration
than those thresholds are shown
File name containing the
current syllable
Date and time of
current syllable
Date and time of
current syllable
Each red dot represents a syllable, the X axis is 'duration' by default, and the Y axis is
mean FM. Note that feature units are scaled, with median at 0 and with a spread of a
single MAD (median absolute deviation) unit. The beginning of the movie is also the
beginning of song development, when songs syllable are relatively unstructured.
Click at the long slider at the bottom, it should turn yellow, and move its thumb to the
right, about ¾ of the way. The movie should now look very different:
We can see 3 nice
clusters, which correspond to the 3 syllable types of the song
produced. To see other features of those clusters click on the Y-axis feature choice (you
can do this as the movie is playing). Clicking on the pitch shows different projections of
the clusters. Moving the mouse into the movie image will show a hand pointer, indicating
that you can move the image as desired. On the bottom right you will see a radio-group
with 3 choices: rotate, pan and zoom - try them all during the movie play.


At this point, our notion of clusters is informal, but in the next chapter you will learn how
to use SA+ to automatically identify the clusters. In this example, we already clustered
the data. To view the clusters select the 'color by cluster' from the color scheme. You can
now see those syllables that we did not cluster in grey color, and those that were
clustered by different colors. In the syllable table, each cluster is identified by a number,
and these numbers correspond to the following colors:
l Red; 2
Blue; 3 Yellow; 4 Lime; 5
Black;
6 Fuchsia; 7
Olive; 8 Silver;
9 Green; 10 Aqua;
Looking at DVD maps after clustering is a useful method for validating that the outcome
of the clustering is reasonable.
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