ISPRS Workshop on Service and Application of Spatial Data Infrastructure, XXXVI(4/W6), Oct.14-16, Hangzhou, China 
270 
{ 
DM^-DeleSuffix(TM); // delete the terminal digit 
M«—DelePrefixD(DM); // delete the started digit 
(ij) F-l(M) // conversion from Morton code of the 
diamond to row/column number 
T<—SuffixD(TM); // extract the orientation of the triangle 
switch(Dir) 
{ 
EAST: // the east neighbor of the triangle 
if(T=0) 
DM<—EdgeDiamondAdjacent(DM,EN); 
if(i<I) TM<-AppendTODM(DM,l); 
else 
TM^AppendTODM(DM,0); 
else 
DM<—EdgeDiamondAdjacent(DM,ES); 
if(j<I) TM^AppendTODM(DM,0); else 
TM<—AppendTODM(DM,l); 
break; 
WEST: // the west neighbor of the triangle 
if(T=0) 
DM<—EdgeDiamondAdjacent(DM,WN); 
if(j>0) TM^AppendTODM(DM,l); 
else 
TM<—AppendTODM(DM,0); 
else 
DM^EdgeDiamondAdjacent(DM,WS); 
if(i>0) TM^AppendTODM(DM,0); 
else 
TM<—AppendTODM(DM, 1); 
break; 
INVERT:if(T=0) 
TM<—AppendTODM(DM,l); 
else 
TM<—AppendTODM(DM,0); 
break;} 
retum(TM) 
} 
7. CONCLUSIONS 
Data organization based on the diamond tessellation has several 
advantages. Diamond geometry is simpler than triangles. Like 
the regular grid, the diamond cell has uniform orientation, radial 
symmetry and translation congruence, thus make it much more 
easier to complete nearly all the spatial operations of the 
discrete data a spherical surface. The diamond hierarchy is 
nested that make it convenient for data organization and 
compressed storage. We use a labeling scheme in which two 
triangles that make up each diamond can be distinguishes 
through add an additional digit to the end of the Quadcodes of 
the diamond. This makes it possible to extend algorithms and 
techniques developed for Quadtree Square meshes to adapt to 
the triangular meshes. 
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ACKNOWLEDGEMENTS 
This work described in the paper is supported by the National 
Natural Science Foundation of China (Under grant 
No.40471108)