Wrapper function to generate an overall SPD for phased dates. Internally this first generates an SPD for each phase. Data may be phased already, alternatively if 'phase' is not provided, this function will automatically bin dates into phases, see phaseCalibrator
. Each phase's distribution is then summed, and the final SPD is normalised to unity.
Optionally 'datingType' can be provided in the data. Only '14C' will be calibrated in the usual way, anything else is assumed to be provided in calendar time. If 'datingType' is not provided, all dates are assumed to be 14C.