Surveyors allow accurate measurements to determine land boundaries. They provide data relevant to the form and contour of the Earth's surface for engineering, mapping and construction projects. Surveyors shall mark and chart the location of the legitimate property lines. Surveyors often use Geographic Information Systems (GIS)—a technology that allows surveyors to visually display spatial information as maps, records, and charts. They then use the findings to advise governments and companies about where to plan their houses, highways and landfills.