long clearSymbolsAlongTrack(string ck)
This method removes the symbols and associated labels, if any, (as created by showSymbolAlongTrackAtTime) from the track with CARIS Key ck.
This method returns 0 upon success, and returns an error code under the following conditions:
- The is no feature with CARIS Key ck
- The feature with CARIS Key ck is not a track.