Determining Building value vs Land value for Depreciation in NYC

[Lyle Cooper]

I own a condo in a multi-unit condominium in Manhattan.  I recently rented my condo out.  I want to depreciate the asset using MACRS over 27.5 years.  The IRS wants the building's value in order to determine depreciation schedule.

How do I determine the land value vs building value of the condominium building?   

Once I have the building value, I can multiply that value by my % ownership.  That should be my numerator in my depreciation calculation.

Thanks