Topography
- The land surveyor is involved in taking measurements using different techniques at every stage of a project.
- (© SETRA, SCANLASER, LEICA GEOSYSTEMS)
In essence, the land surveyor’s role consists of measuring all types of data (angles, distances, altitudes) in order to define the layout of areas of land and the geographic position of different objects. These might include buildings, infrastructure (roads, railways etc), as well as the topography of the land itself (forests, rivers etc). Once the data has been obtained and recorded, it is then used for a variety of purposes.
Topography is indispensable at the different stages of a public works project, with each project presenting a particular challenge according to the specifics of the land and the works being carried out. It is also used in many other areas, from delineation of land ownership to the preservation of the environment.
The techniques used for measurement have evolved rather slowly and unevenly over the years. However, a rapid acceleration has taken place in the last few years with the advent of the use of GPS. It can be said that today topography is truly the height of technology, whilst at the same time conserving a hidden dimension linked to the different conditions of each project! Better yet, it is an integral part of the birth of a new discipline which is now emerging - geomatics engineering.
The authors would particularly like to thank SETRA, Leica Geosystems, Miretopo and Scanlaser, as well as Mr. Francis Delagarde and Mr. Gérard Forquet for their support in the production of this report.
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Linguistically, the term ‘’surveyor’’ relates to the measurement of land and that of “topographer” to the description of a place, both of which are inherent in the modern definition of a land surveyor. His role is to identify the configuration of a place or given geographic area, carry out geometric calculations and work out 2D and 3D graphic representations or models in order to use this information for property or land developments. The land surveyor may also specialize in areas where legal expertise is required such as land ownership etc. for (...)
3D laser scanning study showing unstable cliffs (© Leica Geosystems) GNSS RTK data collection before the start of a road project (© JF Delarue)
The land surveyor is involved at each stage of a project. Prior to commencement he carries out a survey of the area to be developed (the plotting stage). .Then, during the course of the project he supplies the necessary reference points for the progress of the works (setting out). After setting out,amongst other things, collected data is used for plant guidance. During the course of the works the surveyor may also contribute to (...)
Machinery and equipment developed in the last fifteen years or so has radically changed the profession of land surveying ((c) SETRA, MireTopo)
If surveying has undergone major changes in its methods and the results which it achieves, that is mainly due to the advance in the equipment and instruments which the surveyor uses.
This evolution started forty years or so ago with the invention of theodolites which allowed the simultaneous measurement of horizontal and vertical angles. Prior to that innovations had been slow and sporadic but, thereafter progress quickly accelerated. (...)
