Survey work which is carried out by visiting the site to be surveyed.
Establishing and recording real world coordinates of physical features where they exist in the world. Checking and recording the accuracy of map feature depiction by visiting the real world features represented on the map.
The geometry of the geographical features is determined by using terrestrial measurements, e.g. polar measurements and levelling with reference to the geodetic network. The geometric form of field surveyed data is vector. The geographic features are identified at the source by field observations.