Study On Vector Element Evaluation Method For Urban Underground Space Resources Based On GIS

Abstract

Recently the raster unit method and modified variable grid element method have been widely applied to the GIS-based urban underground space resources comprehensive evaluation. The raster unit method needs to divide the area into units, whose size controls accuracy of the assessment. Because the unit boundary is fixed, there are usually data conflicts and lack of information in some units. Therefore, graphical representation of the evaluated results becomes not precise. The modified variable grid element method solves the contradiction between result accuracy and data redundancy, through splitting the area into smaller elements in key and sensitive regions. However, the new vector element method proposed by this article can obtain a clear boundary and accurate calculation result because it is based entirely on the actual unit edge of each factor. Nevertheless, its application is limited by its complex operation. A practical example for underground space resources fuzzy-comprehensive evaluation based on the vector element method is introduced in this paper, together with the key steps for assessment and GIS-Attribute database structure design, which could provide a reference for similar projects.