Process
Modern surveying relies as much on software as hardware. In suitable shallow water areas Light Detection and Ranging (LIDAR) may be used. Equipment can be installed on inflatable craft, such as Zodiacs, small craft, AUVs (Autonomous Underwater Vehicles), UUVs (Unmanned Underwater Vehicles) or large ships, and can include sidescan, single beam and multibeam equipment. At one time different data collection methods and standards were used in collecting hydrographic data for maritime safety and for scientific or engineering bathymetric charts. Increasingly with aid of improved collection techniques and computer processing the data is collected under one standard and extracted for the specific use.
After data is collected, it has to undergo post-processing. A massive amount of data is collected during the typical Hydrographic survey, often several soundings per square foot. Depending on the final use (navigation charts, Digital Terrain Model, volume calculation for dredging, topography, Bathymetry) this data must be thinned out. It must also be error corrected (bad soundings,) and corrected for the effects of tides, waves/heave, water level and water temperature differences (thermoclines.) Usually the surveyor has additional data collection equipment on site to record the data required for correcting the soundings. Final output of charts can be created in a combination of specialty charting software or a CAD package, usually Autocad.
With crowd sourced surveying, although the accuracy of the individual measurements are not as accurate as with a traditional survey, the algorithms used rely on a high data density to produce final results that are more accurate than the single measurements. Comparison against multi-beam surveys indicates an accuracy of around +/- 0.1 - 0.2m.
Read more about this topic: Hydrographic Survey
Famous quotes containing the word process:
“Because her instinct has told her, or because she has been reliably informed, the faded virgin knows that the supreme joys are not for her; she knows by a process of the intellect; but she can feel her deprivation no more than the young mother can feel the hardship of the virgin’s lot.”
—Arnold Bennett (1867–1931)
“come peace or war, the progress of America and Europe
Becomes a long process of deterioration—”
—Robinson Jeffers (1887–1962)
“Any balance we achieve between adult and parental identities, between children’s and our own needs, works only for a time—because, as one father says, “It’s a new ball game just about every week.” So we are always in the process of learning to be parents.”
—Joan Sheingold Ditzion, Dennie, and Palmer Wolf. Ourselves and Our Children, by Boston Women’s Health Book Collective, ch. 2 (1978)