Hamilton County Auditor uses a flawed formula in determining tax assessment values. The formula is only updated every 6 years, and the input data is often inaccurate and incomplete.
Trulia uses a slightly better formula to try to assess market value, though its data is also often inaccurate and/or incomplete.
However, no formula can take the place of an agent being able to assess potential market value based on experience and taking into account factors these formulas do not: condition of property, seller's motivation, range of uses, utility, etc. This is true for ALL properties, residential or commercial.
If you own this property, you might want to think about challenging the tax assessment value to bring it closer to true "market value."