How to find out land value for depreciation

[Praveen Ashok]

My parents used to live in their home, which was bought in 2009. They moved out and started using it as a rental property in June 2016. This is the first year I am doing taxes for this property. Prior years were done by CPAs. So In order to calculate the depreciation:

a. Should the cost of depreciation be the value the property bought in 2009? 

b. If so how can I know the value of land in 2009? Is this available in the county's website?

thank you.