中南大學(xué)測繪工程地理信息系統(tǒng)雙語課程復(fù)習(xí)基本概念整理-資料下載頁
2025-10-10 10:17本頁面
【導(dǎo)讀】information.1）Data:materialdata,number,words,symbols,figure,andimage;graph.landscapedata,itcanbegraphics,imagesandtext,tablesanddigital,etc. understanddata.
【正文】 Advantage: intrinsic description of a worked topology, with the notion of connectivity useful for optimalpaths search. Disadvantages: No information on the relationships between 2D objects is stored in this model 拓?fù)淠Ｐ蛢?yōu)缺點(diǎn) The advantages of topological model 1Be efficient putation of topological queries。 2Because of object sharing, consistency maintenance and updates are easier。 3Each edge geometry is stored only once. The disadvantages of topological model 1Some spatial objects in the database may have no semantics in the real world。 2The plexity of the resulting structure may slow down some operations。 4Display a region might require scanning several adjacent polygons and erasing their mon boundary。 5The input of new object requires the preputation of part of the planar graph. Advantages of TINs:TIN 優(yōu)缺點(diǎn) 中南大學(xué)楊俊山整理 1Adapt to various terrain structures 2Adapt to varying data densities. 3Use as a reduction tool, particularly useful in visualisation. The disadvantages of TINs 1Difficult to constrain triangulations to greatest advantage 2Deficiencies in representing terrain shape parameters: 3Slope 4Curvature The advantages of regular grid DTM 優(yōu)缺點(diǎn) 1Easy to operate by puter。 2 Easy to pute some terrain shape parameters: 3Slope 4Contour ///////////////////////////////////////////////////////// The disadvantages of regular grid DTM 1Difficult to represent the structure and detail of terrain 2Large data The advantages of Quadtree code 1） easy to pute the metric property of polygon； 2） the resolution is variable, which can represent the detail shape with a lower spatial units ； 3） the transfer from quadtree to simple raster structure is easier than other pressed methods ； 4） can to represent the event of a plex polygon with holes。 Delaunay trangulars 性質(zhì)： A、 Circumcircle determining rules： In the circumcircle of a certain triangular, there are no any other points of the discrete point set beside thethree vertex. B、 Maximum— minimum angle rules ： – In the triangular works, the minimal angle of all delaunay trangulars are the maximum. 空間插值方法 Methods of interpolation 1： Nearest value: the value of the nearest data point。 2： Linear interpolation: simple straight line based on two points is used。 3： Spline interpolation(樣條函數(shù)法） : based on three or more points。 中南大學(xué)楊俊山整理 4： Stochastic interpolation(隨機(jī)的） : based on: a pseudorandom number generator and fractal parameter and several points 5： Model based interpolation Raster model Vector model Advantages Advantages 1. Data structure: simple 1. Data structure: strict 2. Overlay operation: easy to realize and effective 2. explicit topology 3. Spatial variety: effective 3. Figure: beautiful 4. Image enlarger Disadvantages Disadvantages 1. Data structure: not strict, need to press 1. Data structure: plex 2. The lack of explicit topology 2. Overlay operation: not effective 3. Figure: not beautiful 3. Spatial variety: not effective 4. can not to do image enlarger
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