Section 103. Acquisition of lands

Whenever  any  real estate or interest
  therein shall be required for any municipal purpose, except as otherwise
  provided by law, the commissioner of public works may  acquire  for  the
  city  the  necessary  land  and real estate by gift or by purchase, at a
  price approved by the board of estimate and  apportionment,  or  by  the
  proceedings  specified  in  the  eminent domain procedure law, or in the
  case of property  required  for  street  purposes,  by  the  proceedings
  provided  by  law  for  acquiring  and ascertaining damages for property
  taken for purposes of street openings.