A Multi-scale GIS Scheme and Its Data Model

This paper proposes an applicable multi-scale GIS scheme and realize it with an appropriate spatial data model.The advantages and disadvantages of four typical multi-scale GIS schemes are analyzed.Based on the analysis,a new scheme-layered,leveled and partitioned scheme is proposed.In the scheme,the object district is divided in several scale layers.Then the minimum scale layer is divided into several smaller scale levels.The nearby larger scale layer is partitioned into several sub districts.Similarly,each sub district is divided into smaller levels,and nearby larger layer is partitioned into sub districts,and so on.Each district with its levels is stored in one database.Based on the spatial data model designed by the authors,according to map generalization methods,a multi-scale GIS data model which is suitable for the new scheme is successfully developed.For the purpose of verifying the validity and feasibility of the new scheme and model,a prototype of multi-scale GIS software is written.Experiments prove that the new scheme and model are really valid and feasible.