R help - Nov 2005 - Temporal disaggregation using interpolation splines

Hi,

this is a newbie question. Would it be able to convert e.g. annual
time series of flow data (or an index series) into quarterly data using
interpolation splines by means of an existing R-function? The problem is,
that the average value of the computed quarterly values must be the annual
value, i.e. the spline should cross the annual values (in a stairs-line
plot) in the middle of every annual step.

With many thanks for every hint
Albrecht Kauffmann