Post by gareth evans
Are they audio frequency spectra?
For a submarine, (some of?) the interesting variables are time,
frequency, direction. In common waterfall displays, e.g. those used in
radio, the typical axes are frequency and time, with color coding for
signal strength. This sort is useful for identification of a noise
source. But it's easy to imagine, and I have seen in movies (with the
usual "Hollywood" errors), angle as one of the axes.
Obviously in passive sonar, distance has to be estimated based on other
knowledge -- water characteristics, the sound profile of the source,
etc. If you have good enough data, you can make distance one of the