Computation of local topologic invariant in spherical surface quaternary triangular mesh and its application

Spherical surface QTM (quaternary triangular mesh) is one of an efficient tool to deal with the global data because of its advantages of multi-resolution and hierarchy. Like three topological number, local topologic invariant in it is also one of the important basic parameter to computer relation among spherical objects. Definition and properties of local topologic invariant will be discussed firstly. Then, we develop a new algorithm topo_para to calculate the local topological invariant with three topological numbers n3(p). In the end, application of the algorithm topo_para is given as follows: computing the Euler number of a spherical surface raster region with local topological invariant.