Aerial topographic surveys are undertaken for larger tracts of land where it is not cost effective to do the topo by conventional means. However, our role as the land surveyor is critical to the accuracy of the aerial topo. Aerial panels have to be placed on the ground and become reference points for the mapping of the aerial topo. The land surveyor provides the mapping company with the coordinates and elevations of the panels for their use in extrapolating the contours of the topo. In addition, the land surveyor ties the location of property corners in the area so that the topo can be properly mapped in relation to the property lines of the parcel.