【正文】 s, various information dynamic, rhythm, rhythm, cycle and distribution. The general is the image of geographic information, digital geographic information and file information. A variety of geographic information of modern geography through observation, statistics, document retrieval, aerial survey, ground measurements, the aircraft measurement for information on the surface of the earth and space condition.The concept of geographic information system (Geographical Information System。 GIS): supported by puter hardware, all kinds of geographic information according to the spatial distribution, in a certain format input, storage, retrieval, update, display, graphics and prehensive analysis of the technology system. It contains data, symbol and image etc..The concept of Measurement Science (Surveying): surveying is the study of how to determine the location of the ground plane points and elevation, the topography of the earth39。s surface and other information of Surveying and mapping (with map and topographic map), and study the earth39。s size and shape of a science.Determination of the concept refers to the use of measuring instruments and methods, through the measurement and calculation, obtain the measured data of the ground point, or to the topography of the earth39。s surface according to a certain proportion shrinking as topography, for scientific research, the national economic construction and planning design.Survey and design concept is the planning drawing design good building, structure location (position and Gao Cheng) with the measurement instrument and the measurement method on ground calibration as the basis for construction. Two, surveying and mapping science research objectObject mapping studies, usually is the surface of the earth (including land and sea) and fixtures. With the continuous development of science and technology, the research object will be extended to the distant space and other planets.Three, the task of Surveying and mappingTypically, surveying and mapping tasks are divided into three aspects as follows:1, the surface of the earth or the earth39。s surface shape and size of the local region mapping topographic maps from the field to the drawings (mapping or determination)2, the drawing design good engineering building, the instrument and method calibration to the field from drawings to the field (setting or setting).3, under construction and pletion of the building deformation monitoring, regular deformation observation.Such as France39。s Barcelona outburst of an arch dam, the dam is an example of the lack of necessary observation and caused great disaster. The dam was built in 1954, destroyed in 1959 December. The dam burst, store flood rushing downstream water level rise, instant. Depth of 7 15 meters, width of a kilometer to 70 km / h speed down speed, lasted 45 minutes, downstream 10 km Ferre eggplant, city in ruins before the dam, 8 kilometers a barracks 500 soldiers died. To this end, the French government set up a mission check. According to the survey said: because the dam slope local rock weak, the abutment inhomogeneous deformation and landslide caused by the dam burst. Set no observation instruments during the dam operation, building on the lack of regular inspection and observation of deformation before failure, failed to fully understand the dam reinforcement remedial measures, did not make the corresponding etc, is one of the most important causes of dam failure.The investigation that the dam failure lesson of the main is dam observation shall be equipped with a sufficient number of personnel and equipment, systematic observation of dam.So far, in water conservancy technology theory, is also very difficult to solve the problems in water conservancy project all, such as the stress state and stability calculation, the flow state, hydrological and engineering geological conditions. However, the modern practice of observation has to a great extent can make up for its shortings. For example, a dam dynamic, basically be by the dam external deformation observation, internal (stress, strain and so on) observation and seepage observation three timely, fully tested, and found problems in a timely manner. The deformation observation of dam in the world of maintenance, and some projects together, are put in the first place.In fact, the vast majority of the destruction of the dam, don39。t happen overnight, but there is a process from quantitative change to qualitative change. So, even if the dam has some defects, inappropriate factors or design theory, geological survey and construction quality, if through carefully observation, inspection, can be timely discovered and remedy.France39。s Barcelona arch dam after the crash, the deformation of dam observation work more attention, since the international conference to dam deformation observation of dam as an important content included in the agenda, and published a large number of observation data. The meeting in many countries (Committee) or government, to monitor reservoir or dam safety and much stricter regulations.Four, surveying and mapping science classificationSurveying and mapping science as a subject, can be divided into several independent discipline:1, geodesy (geodesy): is the space in a certain time reference system, measurement and description of the earth and other planetary bodies of a discipline. Another definition is studied in larger regional or global 3D geodetic control network, gravity network, determination of the earth39。s shape, size and the earth39。s gravity field and its variation theory, technology and method of the subject. The main contents are: triangulation, traverse survey, leveling, astronomical measurement, gravity measurement, satellite geodesy, very long baseline interferometry, inertial measurement, ellipsoidal geodesy, the earth shape theory and surveying adjustment etc..[geodesy Knowledge Window] geodesy is one of the oldest Appli