If you want to know where to put up a fence so that you don't encroach into your neighbor's yard, you do a survey, which is a graphical representation of a piece of real estate, including dimensions and features. Surveys have legal weight. For example, an attorney can present a licensed surveyor's work in court to settle a land boundary dispute between neighbors. Surveyors use different tools, such as compasses, to do their jobs. One important tool is the survey marker, which the surveyor uses to set boundaries.

Survey Markers
   A surveyor places survey markers to label major points on the land's surface. For instance, she may place marks at the northeast and southwest corners of a piece of land to physically represent the boundaries. The legal description for a property, which is the land's dimensions in words, may reference the placed markers. A property's legal description is needed for real estate documents such as deeds and mortgages.
Types of Markers
   Markers today come in various forms, including iron pins and brass discs. Surveyors used less permanent materials, such as wood stakes, local landmarks and stones, in the past. The surveyor places the marker into the ground and secures it when finished, but may tie ribbons on trees and use other temporary markers while doing field work. Private surveyors usually inscribe their markers with information that easily identifies them, such as their state license or certificate number. A surveyor for a government project may use the project name and number or another official label approved for use by the agency.
The Legal Boundaries
   Survey markers represent the legal boundaries of a person's property. Moving markers may create land line disputes with neighbors. For example, John's neighbor Sandy moves his northwest marker 3 feet in so she can have her fence cross his land. John may have to take Sandy to court to dispute the placement. Since Sandy moved the marker, the surveyor John hired for the case will have to do research and resurvey the land to fix the problem to make John's case in court.
You Can't Move Markers
   It's illegal to remove or alter permanent survey markers in some states, including California, but penalties vary. Only licensed surveyors and government officials with a permissible purpose, such as a land resurvey, should remove or alter permanent survey markers. A property owner should arrange for a licensed surveyor to survey his property if he thinks there's a problem with his markers to avoid breaking the law.