To determine the market value of vacant land (any property with no buildings), you must look at a number of factors. It's a little different than trying to determine the value of a residential or commercial property. The market value of any property, put simply, is whatever someone is willing to pay for that property and other similar properties. That value, of course, is based on a few different attributes.
Look at comparable properties that have sold in the past two or three months. Try to find properties in a similar location that are the same size and type as the property for which you are trying to determine a value. If a similar property is selling for $160,000, your property is probably worth something close to that.
Consider where the property is located. Location is an important factor when determining market value. Two completely identical vacant lots in two different cities can have values that differ by thousands of dollars, if not more. There can even be extreme differences in plots of land a few blocks away from each other. If the land is situated in an area of rapid expansion, or if it is near a busy financial or retail district in a large city, it is worth a lot more than if it were located along a country road in a small town.
Factor in any unique attributes that the property may have. If the vacant lot is zoned for commercial, it might be worth more than if it were zoned for residential use. In an area that does a lot of logging, the property will be worth more if it has an abundance of hardwood trees. A vacant lot that is situated on a body of water, or that provides a great view or other marketable value (such as a fruit orchard), will be worth more than a bare plot of land.
Remember that timing can change the market value of vacant land.This is mostly due to factors in the real estate market (whether sale prices are up or down), but there are other reasons the value might regularly change. With an orchard, for example, the market value is highest when the fruit is ready for sale. If the lot is located in a city, it is at its highest market value while the city is growing around it, and while land is scarce. Years later, if the neighborhood sees a period of decline, the property would be worth considerably less.