tsc_CircleObservation

This a subclass of tsc_PointObservation, and contains a tsc_RawCircle coordinate.  This type of observation is used to store measurements taken by a total station.

Such an observation can only be appended to the database while a current station setup exists.

Each raw circle observation requires environment information - the station and the target - which are supplied by the tsc_TsEnvironment class and can be sourced from the database or the tsc_TsModes object.  An instance of tsc_TsEnvironment should be passed in when setting the tsc_RawCircle on the tsc_CircleObservation to ensure the correct environment information is stored with the point.