Modern techniques for topographic surveys in the land survey unit

Abstract

The introduction describes the equipment and software available presently, in the Land Survey unit, what the software can produce. It also explains the aim of this exposition. "Present Techniques Used", describes the techniques that are presently used, highlighting the problems encountered when applying them. The procedures used, for producing planimetric surveys are featured, and illustrating the need of introducing coding. "Introducing Coding", deals with a brief explanation of how one can create a code list with the software available in the unit. Although brief, it shows step by step procedures from creating to uploading codes in the total station. The commands used in this whole operation are tabled in this chapter. Stringlines are also mentioned and there importance. The chapter outlines the process in using the total station for field operation using codes. This is a slow process, but with time the surveyor will tolerate the time consuming process, as it will result in an accurate final product. Before processing a field survey using this software, the program has to be prepared in order for the software to recognize the codes that had been used by the operator using the total station. The importance of the Look Up table is highlighted and step by step procedures are illustrated. Downloading is clarified, picturing the dialog boxes that appears on the screen when using commands. Field coding allows the crew to become draughtsmen and the many field book sketches are eliminated. ''Three Dimensional Surveys''. With the system of recording and coding, using the same software, three-dimensional surveys can be produced. The topographic section can take a step further, i.e. creating digital terrain models from surveys that are carried out. Validation and modeling are featured in step by step commands for the DTM to be created. "Beyond 2000". Presently the surveyor sets out alignments by scaling mostly from 1 :2500 scale schemes or where available using 1 :500 scale surveys. With the introduction of setting out by coordinates in the near future, the problems encountered when scaling will be diminished. Another feature, which will be implemented in the L.S.U. in the future, is the use of G.P.S. (Global Position System) for complementing the technique, which will be used by the surveyor.