A NEW EVALUATION METHOD FOR URBAN UNDERGROUND SPACE RESOURCES IN THE VECTOR UNIT WAY

Currently raster unit method and modified variable grid element method were 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 the accuracy of assessment. Because the unit boundary is fixed, there are usually data conflicts and information lack in some units, so the graphical representation of evaluation results could not be precise. The modified variable grid element method solves the contradiction between results accuracy and data redundancy, through splitting the area into smaller element in the key and sensitive regions. The new vector element method can obtain a clear boundary and accurate calculation result because it is based entirely on the actual unit edge of each factor, but its application is limited by a difficult approach and complex operation. A practical example for underground space resources fuzzy-comprehensive evaluation based on the vector element method was introduced in this paper, together with the key steps for assessment calculating and GIS-Attribute database structure design, which could provide a reference for some similar projects.