Study On The Uncertainties Of The Products Of GIS

Information has uncertainty (P F Fisher commonly, 2002), this is a fact that has been approved extensive by scientific and technical worker. According to the statistics: Human being exercises the information being put into use , has 75% ~ 80% become the hot topic of conversation that scientific and technical worker discusses already above 80% with location investigation and discussion in connection with whose uncertainty. The map is that space distribution and other special subject expressing a geographic element is attribute have the close mathematics basis and the sign system science data , the drawing having entirely is synthesizing theory system , it is bearing the weight of fundamental data transmission function.The GIS digital map has been under holding out combining with modern computer art , data base technology , Multimedia etc. then , the tradition map has become the data base data that the vector or the grid type data is composed of , it can synthesize the data that the various data stems from and the data glove , data helmet being able to generate new information, and then supposing the real technology even with screen display , plotting instrument , printer, have outputted.This paper Figure map picture basic that the map and digitization measure from GIS figure stems from a thesis starting, the main distinction having analyzed depends on that the GIS map has increased large amount of picture basic , these new picture basic that the GIS data base stores per se and not directly is to come into being by the fact that the GIS space analyses a function; And then, new picture basic coming into being has carried out classification and induction on GIS map.The main conclusions as following1. Line uncertainty:(1) becomes inverse ratio with ascertaining the distance square owing rectilinear both ends point.(2) Indeterminacy direct proportion with ascertaining the coordinate value owing rectilinear both ends point.2. Uncertainty of fixed point unit by distance(1) counting-started point coordinates indeterminacy over fixed point indeterminacy is a constant;(2) inserts an impact of distance accuracy over that indeterminacy for the law fixing value, is theory value , does not contain error's as for the fixed point allocating distance's;(3) angles of position indeterminacy over fixed point accuracy arrives at end point distance direct proportion big or small with inserting point.3. Uncertainty of fixed point unit by proportion : (1) interpolative fixed point, be not big , midpoint accuracy is maximal.(2) outsides insert fixed point , accuracy is lower than interpolative fixed point commonly, with P and P2 the distance size assumes the rapid increase trend, and the trend is obvious.4. Uncertainty of fixed point unit by intersection of straight line(1) place indeterminacy minimum value is located in 90 degree, and is reduces gradually in order to being accuracy symmetrically time 90 degree to two flanks;(2) when in 60 ~ 120 degree, and accuracy with angle change is not notable. Accuracy is lowest when being smaller than 20 160 degree of degree and greater than, the more the angle approaches 0 (or 180) degree, accuracy reduces rapidly.Here are the creating works as following,(1) firstly, the type analyzing new picture basic coming into being carries out induction on GIS space arranging, and the uncertainty to generated picture basic carries out classification. Point out new GIS picture basic coming into being but be that unitary output , combination output and superimposition have exported three major kinds, and have carried out induction on respective uncertainty mark;(2) has become an example first unit mechanically with the vector , has analysed unit of superimposition , unit of line cross spider, inserting three kind the uncertainty generating way such as point unit, function equation, and induction using Mathematica mathematics software to have drawn indeterminacy have got the corresponding conclusion; (3) pair of superimposition has analysed the common existence of middle coordinate matrixing job , the data respectively having carried out some express highway coordinates studying, and being tied in wedlock on parameter matrixing law , polynomial simulation law , uncertainty across ellipsoid coordinate matrixing has carried out a thesis studying.