Look for the property lines. The site map will have a thick line at the perimeter which illustrates the boundaries of your property. These will either be marked in a different colored pen or will be referenced in the site map key. Check these to determine if your property size is large enough to incorporate the building or landscape projects you may be considering. Also determine how big the property is in relation to neighboring houses. This can help you negotiate the sale price.
Read the contour lines. These lines indicate two important things. The first is the slope of the property. The closer these lines are together, the steeper the slope is. This is very important for drainage, plumbing, landscaping and even the building plans themselves. Secondly, these lines show areas that may need retaining walls in the future.
Examine the placement of sidewalks, drains and transportation indicators. These will be fairly obvious and are usually marked in the site map key. It is important to determine how easily you will have access from the property to the nearest roads. Check if the sidewalks run near or on your property, and how close they are to your boundary. Finally, the site map will show you any significant draining systems which are coming into your property. New construction may require installing install additional or larger pipes and drains if the present system isn't adequate.
Check the building lines, which are located inside the property lines. These are vitally important because they help determine how large your building can be in relation to the size of the property. For example, local ordinances state the distances (set backs) it must be from the property line, fences, sidewalks and drains. Use this to determine the size of the building or project and in what shape it can be built.
Determine the orientation of both the property and the structures on it. Somewhere on the should be a drawn compass indicating overall direction. Also check how the house is positioned in the street, which direction it faces and the directions windows and driveway face. Perhaps you do not want the master bedroom windows facing west, or maybe you prefer your driveway open onto a side street rather than the main road. All of this will be indicated on the map.