The appraiser will look at the current use of the property and determine its market value based on that information. They'll also look at other factors like zoning laws, easements, and deed restrictions that might affect the sale of the property.
Above all, it's important to remember that property appraisal is subjective. The results of an appraisal are usually only as good as the information that is provided by the person requesting it. An inaccurate appraisal can lead to some real problems down the road.