Baseline (geodesy)
As a base or base line in which is Geodesy and other areas of technology a precisely measured distance referred to may be determined by the other of the position of points by angle measurement.
measurement
Distance measurement
In the optical distance measurement - z. B. with a scissors telescope or in nautical or military location - it is the several decimeters long "base" on whose end points the parallactic angle to the target point is measured.
Surveying
In geodesy and photogrammetry , the “base” usually represents the side of a triangle or the common side of many triangles, which - measured with high precision - gives an entire surveying network its geometric scale . Special forms of this procedure are:
- the classic Invar basic measurement with calibrated measuring wires to determine the scale of a triangulation . It delivers mm accuracy over many kilometers - see special article basic measurement
- precise electronic distance measurement between high-ranking surveying points , especially in the first-order network
- the previously often used distance measurement with a 2-meter base staff
- In terrestrial photogrammetry, the staking out of a "base" on which stereo recordings are made with the measuring camera .
photography
In photography , the basis is that line (which today only measures mm… cm) on which the measurement of a sectional image rangefinder is based. The more common type of focusing today, however, is distance measurement with an infrared beam.
Measuring equipment
Possible measuring devices for baselines are (in approximately historical order):
- Ruler , folding rule or similar measuring stick for the geometry
- Measuring chains and twelve-link chains for measurement
- Measuring cords or ropes
- Jump of the thumb and other parallax measurements
- Measuring rod , scale equipment , batter boards for construction
- Prism scale , Abschiebedreiecke etc. for geometric drawings
- Micrometers or dial gauges , flat plate micrometers for optics and precision mechanics
- Running miles , scissors telescope , patent u. a. Logging for nautical purposes
- general: tape measure , roll meter and similar measuring equipment from 1 to 100 m in length.
Especially in geodesy and astronomy:
- optical distance measurement , horizontal or vertical base staff
- Measuring table , telescopic sight
- astronomical heliometer , annual parallax
- Control point measurement, stereo comparator
- Radar and Shoran
- Invar wire for the basic measurement
- Electronic distance measurement , transit time measurement
- Satellite trilateration and Doppler measurements
- Satellite Laser Ranging (SLR)
- Global Positioning System (GPS) and dGPS
- VLBI and terrestrial interferometry .