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L14 modern geodetic technique.pptx
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Geodesy L 14 Modern geodetic equipment
TOTAL STATION
NORTH Y Z X EAST Harry Williams, 3
reflector The total station works by firing an infrared laser beam at a reflector mounted on a stadia rod. The distance between the total station and the reflector is calculated based on the time taken for the beam to reflect back to the total station. Total stations were originally developed for the construction industry – e. g. surveying new roads, laying out building foundations, utility lines etc. .
NORTH ANGLE Example based on UTM: TAN DIS Y CE TOTAL STATION: UTM = 3676595 m N 672156 m E Y=150 m; X=70 m UNKNOWN POINT UTM=3676595 -150 3676445 m N 672156 +70 672226 m E X 5
Most total stations have the ability to record survey data as a digital file, which can be imported to a PC-based GIS program. MAP 6
Why use a total station? • • • 1. Field work is carried out very fast. 2. Accuracy of measurement is high. 3. Manual errors involved in reading and recording are eliminated. 4. Calculation of coordinates is very fast and accurate. Even corrections for temperature and pressure automatically made. 5. Computers can be employed for map making and plotting contour and cross-sections. Contour intervals and scales can be changed in no time.
When do you use a total station? • For mapping small areas (the range of a total station is around 2 miles or so – assuming you have good lines of sight). A good example would be mapping an archaeological dig site. • There are many other applications in earth science that require great accuracy e. g. monitoring cliff erosion, glacier movement, changes in beach profiles, sand dune movement. . and so on.
Comparison of total station and GPS
SMART STATION • • • Benefits of Smart. Station: ■ Control points are not needed; ■ No awkward traversing required; ■ Consistent high accuracy; ■ Complete survey quicker; ■ Traversing skills not required;
Robotic total stations • Allows the operator to control the instrument from a distance via remote control • This elliminates the need of an assistant staf member, as the operator holds the reflector and controls the total station from the observed point
