Geography Reference
In-Depth Information
Fig. 1 Coding bi-temporal changes with variations of pitch
Fig. 2 Coding multi-temporal changes with variations of pitch
• either proportional to the change of values, or
• using always a constant pitch difference (e.g. a second up for an increase and a
second down for a decrease), no matter how large the value difference is.
The latter case can be perceived much easier by the human; however, this goes
along with a loss of information. If pitch differences are required, our experiences
show that using standard differences from the musical scale (i.e. second, third, etc.)
are more convenient to the human ear in order to represent equidistant class values
compared to a strict transformation of value differences into frequencies (i.e. using
the unit Hertz). Finally, it has to be mentioned that no studies are known that reveal
usability recommendations concerning the total number of sounds (i.e. the total
number of different values that can be represented), the suitable tone interval, and
the total number of time stamps that can be perceived and reliably recognized by
the user.
