In: Wagner W„ Székely, B. (eds.): ISPRS TC VII Symposium - 100 Years ISPRS, Vienna, Austria, July 5-7, 2010, IAPRS, Vol. XXXVIII, Part 7B 
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Figure 12: Lunar DEM 
The spherical Geometry Clipmaps request the DEM 
size equal to image half size in same LOD layer. For 
example, if image size is 1024x1024, then the DEM 
size must be 512x512. So we must resample the low 
resolution DEM data with bi-linear interpolation 
method. 
Finally, we built the pyramid of DEM and image. The 
amounts of pyramid layer are nine. The test results are 
Figure 13: Lunar front face 3D map 
Figure 14: Lunar back face 3D map 
Figure 15: Lunar local zone 3D map 
Figure 16: Different resolution mosaic 3D map 
Figure 17: The high resolution 3D map in Appio 15 
zone 
4.2 Conclusion and Future Work 
We collected Lunar DEM and remote image, 
eliminated data’s gross error, resampled the data, built 
the data pyramid, and rendered the global lunar 3D 
map real time. The frame of rendering is independent 
on size of data. The future works include: 
(1) The solution of distortion in lunar pole 
Using the Eq.(l) performing in GPU, We can 
transform the planar terrain to spherical terrain. But 
the problem of projection distortion in lunar pole will 
worsen the rendering effect. The projection result be 
shown in Figure 18. Because there are best zone to 
human explore moon and build lunar base, so we must 
optimize the LOD and projection algorithm to 
improve the rendering result. 
Figure 18: projection distortion in lunar pole 
(2) Higher precision lunar terrain rendering 
With the restriction of data gained means, the lunar