Convert from shaftment [ancient] to gigameter

Unit Definition (shaftment [ancient])
A shaftment, when used as a unit of length, is usually six inches or two palms, i.e. 15.24 cm (for the international inch). It is thought to be the distance from the tip of the outstretched thumb to the other side of the palm.In English this unit has mostly fallen out of use, as do others based on the human arm: digit (1/8 shaftment), finger (7/48 shaftment), palm (½ shaftment) hand (2/3 shaftment), span (1½ shaftments), cubit (3 shaftments) and ell (7½ shaftments).

Unit Definition (gigameter)
The Gigameter (or Gigametre) a metric unit of distance equal to one million kilometers or about 621,371.2 miles. It is seldom used, but this unit would be a good yardstick for the inner Solar System: the distance from the earth to the sun is about 149.60 gigameters.