Section 237. Maps and recommendations

Such planning commission may cause to
  be made a map or maps of said city or village or any portion thereof, or
  of  any  land  outside  the limits of said city or village so near or so
  related thereto that in the  opinion  of  said  planning  commission  it
  should  be  so mapped.   Such plans may show not only such matters as by
  law have been or may be referred to the planning  commission,  but  also
  any and all matters and things with relation to the plan of said city or
  village  which  to  said  planning commission seem necessary and proper,
  including recommendations and changes suggested by it; and any report at
  any time made, may include any of the above.  Such  planning  commission
  may  obtain expert assistance in the making of any such maps or reports,
  or in the investigations necessary and proper with relation thereto.