Then measuring horizontal and vertical distance and angles, and recording the field measurements, usually in the field notebook. The field problems given herein might in practice become parts of extended surveys. A survey consists a lot of office work like correcting the field measurements to meet the codes that are required. Also when doing office work they are responsible to find the plotting of the maps, profiles, and cross-sections and calculating area of land and volumes of the earth that you would be working with. Sources of error is the measurements of surveying, instrumental errors arise from imperfections or faulty adjustment of the devices with which measurements.
Personal errors occur through the observer's inability to read the instruments exactly.
Natural errors occur from variations in the phenomena of nature. When surveying, find the distance between two points is easy. Though frequently slope distances are measured, they're reduced to their equivalent on the horizontal projection before being used. When finding the elevation of the point near the surface of the earth is its vertical distance above or below and arbitrarily assumed level surface or curved surface every element of which is normal to the plumb line. The level surface used for reference is called the datum.