الفهرس 
IntroductionOnly 14 pages are availabe for public view
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Abstract
Water-covering more than 70% of the earth`s surface, is of key importance to life on our planet. Marine and inland waters perform a large number of vital ecological and economic functions.These functions are such the supply of water and food, provision of transport routes, and the regulation of the climate.
Hydrographic survey provides the main basic data the responsible, future-oriented use and management of water as a biotope and economic area.The main objective of Hydrographic survey is to delineate the shape of a portion of the earth`s surface concealed by water.The surface to be mapped can not be observed directly or accupied, so it is necessary to infer topography from depth measurements.This process is simply achieved by deducing underwater topography from numerous discrete observations of depth at known positions throughtout the survey area.The quality of the final product depends on accuracy and destiny of these observations.
So accuracy investigation of hydrographic survey is of a great importance task in order to evalute the final product accuracy.This will also help in making decision in choosing the suitable techniques and instruments in performing the hydrography survey. And this will also depend on the purpose of the required hydrographic survey. All sources of errors that may affect data observations in Hydrographic survey must be considered.
The main objective of the practical test in thesis is to make hydrographic survey Sea bed contour maps for breakwaters area at ras elbar city in order to evaluate the impact of the executed project on the coastal zone.
Before performing this job some office preparations are done such as determining te limits of the area to be surveyed, preprations of sounding lines that cover this area and feeding the used computer software with the co-ordinates of these lines, and collecting all available surveying data regarding this area.
In fieldwork some instruments are used to collect data observations such as water level, horizontal coordinates, and depth measurements.