Vertical positioning is usually done by levelling, which is a technique for measuring differences in height between established points relative to a datum or base point. Over short distances, levelling telescopes are used to view a staff or pole and, with the aid of a bar code, the height is recorded in relation to the previous station.
Elevation heights can also be derived with satellite receivers, albeit usually with somewhat less accuracy than for traditional precise levelling. However, the accuracy of satellite receivers may be similar if traditional levelling has to be used over a long distance. Laser altimetry is employed for large areas, but its accuracy is not as good as levelling or
Describe and explain standard spatial (and non-spatial) data input techniques (non RS) including the management of the data collection process (level 1 and 2).