Boundary, Coboundary, Six Groups Topology and ‘one Face with Three Layers' in 3d Gis

On recognition to boundary and coboundary in ISO TC211 Geographic Information “Spatial schema” International Standard. The author modify ‘five-group relations’, which the authors have proposed formerly, to ‘six-group relations’. A new concept of 'One face with three layers' in 3D GIS topological relation is given in the paper. It is a supplement and development for relation of ‘Face-ExteriorRing-InteriorRing-PositiveSolid-NegativeSolid’ in the ‘Five group relations’. 'One face with three layers' supposes that one face has three layers, i.e. positive layer, middle layer and negative layer. Positive layer and negative layer are divided separately, middle layer overlap division of positive layer and negative layer. In this way, the integrality of a nature face is retained, division of positive side and negative side are isolated, but have some connection through middle layer. Data structure of ‘One face with three layers’ is designed in the paper. If construction 3D topologic relation in this way, inquire of one polyhedron’s adjacent polyhedrons is very easy. Last, the author expands the concept of “One face with three layers” to 2DGIS, to deal with the line object like freeway, railway and river, which may be nature boundary of districts.