Statistical Analysis Of Positional Uncertainty Of Road Networks In Volunteered Geographical Information

Volunteered geographical information(VGI)attracts many researches because of its high availability and variety.For many organizations,however,it is important that the quality of VGI can get guaranteed.Position is a fundamental attribute of geographical data leading to positional accuracy a hot point in the related researches.Under the buffer-zone method,reference datasets following strict collection standard have been used to assess positional accuracy of map-based VGIs.This paper involves the following studies on(1)The theoretical buffer radii.The assessment results of positional accuracy,with the conventional buffer-zone method,are strongly and positively correlated to the buffer radii.Besides,the buffer-zone method is a concept that has not been subjected to rigorous theoretical and experimental investigations.This study discusses the construction of buffer zone statistically,then,it proposes the statistically defined buffer-zone method providing theoretical basis to the manipulator.The statistically defined buffer-zone method,however,is uneasy for practical use,this study further takes the corresponding envelope approximation as the alternative in practice.The numerical simulations show that the statistically defined buffer-zone method is equivalent to its envelope approximation for the assessment of positional accuracy;(2)Analysis of the positional uncertainty of road networks in VGI.VGI comes from wide sources,which makes error and accuracy are not sufficient to describe the positional quality of road networks in VGI.This study involves the confidence level embedded in the statistically defined buffer zone into the positional accuracy,leading to a measure of positional uncertainty which could provide a more reliable and reasonable measure for the quality assessment of road networks in VGI.This paper set a standard for error research in VGI.Based on the existing problems within the positional accuracy assessment under buffer-zone method and statistics,this paper proposed statistically defined buffer zone and further investigated the positional uncertainty of road networks in VGI.