| With the development of modern aerospace technology, satellite remote sensing technology, modern mapping techniques and computer technology, Earth patterns and the global economic situation can be described using the figures. "Digital Earth" has already widely known. And as one of technical support GIS has made considerable progress. GIS is widely used in various industries, which promotes the social progress and human development so that people can ride on the information superhighway while they enjoy the facility caused by multifarious information.The key of establishing GIS is how to collection, analysis, collation and proper use of GIS data. The papers on GIS front-end data analysis and research, explore processing method of the familiar wrongs which in the process of GIS front-end data collection.The thesis analysis and research GIS front-end data from seven aspects. Chapter 1, elaborate the present status, applications status and the future development trends of GIS; Chapter 2, relate the meaning of data and data types; Chapter 3, elaborate the measure dimensions of the data; Chapter 4, discuss the data source of GIS; Chapter 5, analysis to the data of GIS; Chapter 6, combine living examples to explore common mistakes' data handling in GIS head data process; Chapter 7, tag.The information is used to load data carriers. Data can be documented some identifiable physical symbols. The concrete form of the data is varied, such as the text, sound, picture and so on. Data is information carriers, but not information. Only by collecting and processing data can be turned into information. GIS data has three basic characteristics of attributes, space and time Data can be divided into three types: special feature data (the position data), time attributes data (the dimension data) and special attributes data (the non-position data).To describe the geographical world, everything must be identified, classified and named. Identification, classification and naming are measurements of components, and they use different reference standards or yardsticks. Measure the measure dimensions of GIS data from rough to detailed have four measure layers, there are one by one in order for assigned by naming quantity, the sequence quantity, alternation quantity and ratioquantity.Data is the soul of GIS. Only having the good data, we can establish a good GIS. The data source of GIS is a pivot of Chapter 4 of this thesis. Because of the application purpose dissimilarity, and the profession needed dissimilarity, makes the geography space data have differentiate whether in contents of data and structure, or emphasize particularly on focus and requirements have the certain difference. So different GIS systems are differentiated data sources, synthesize the circumstance of each facet, GIS data source mainly has six aspects: The Aerospace remote sensing surveying; map digitization; all field data collection; Synthetic aperture radar, SAR; close-range photograph; Other data.Based on the basic concept of spatial data quantity, the basic feature, the data quantity etc, Chapter 5 explore some methods how to build up the spatial data quantity system and the quantity control. GIS data has the basic characteristics, such as selectivity, dependability, timeliness, completely, detailed and comprehensive etc. The factor that affects GIS data quantity mainly has three aspects, they are: The space phenomenon itself volatility, the space phenomenon expression and Spatial data handling error. The GIS error mainly contained observation error, attribute error, processing errors, output error, application error, logic error and Geometric errors etc.GIS quality evaluation system includes the quantity evaluation process , multi-criteria evaluation of the timeliness and exclusively, testing and reporting of data etc. The control method of the spatial data quantity has the handicraft method, metadata method and Geographic-related method.In the process of collecting and processing there will produce data errors. Processing the mistake data is a complex systems engineering. GIS data being analyzed and investigated should run through the whole process of setting up a GIS system. In order to ensure data accurately and reliably, the wrong data must be exclude. Chapter 6 of this thesis make a preliminary study about data errors in the process of front-end data collection, and give some solutions according to the practice in my work. |
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