The International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences. Vol. XXXVII. Part BI. Beijing 2008 
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Figure 6. Remaining tree data 
3.3 Examination of Monochrome Shaded Point Map 
A monochrome shaded point map is primarily used to examine 
the state of the filtering of bare land. Figure 7 shows a 
monochrome shaded point map of an area along a river. When 
we focus on the bridge in Figure 7, the accentuated display of 
the monochrome shaded map against the background confirms 
that the filtering has been implemented accurately. When we 
focus on the bank, elimination of the ground data is observed at 
the places indicated by arrows. A similar elimination of the 
ground data is also observed on the top of the slope of the road. 
As the topography is represented by the shaded map in the 
background, it can be concluded that at these places the ground 
data have been measured and then erroneously eliminated 
during the filtering. 
As mentioned above, the use of a monochrome shaded point 
map is an effective method of detecting point clouds 
erroneously eliminated during the filtering process. 
Figure 7. Examination Result 
Figure 8 shows QC/QA maps of a forested area. As the 
monochrome shaded point map cannot be used to examine a 
forested area, as mentioned above, the color-shaded map is used. 
Figure 9 shows QC/QA maps of an area with a bridge. DEM 
used in a color-shaded map is created from ground data as TIN. 
As shown in Figure 9(b), though the data have actually been 
eliminated, as they form TIN with data on the other side of the 
river, the bridge appears to remain on the map. A monochrome 
shaded point map is effective for the examination of a bridge 
over a narrow river. 
Figure 10 shows QC/QA maps of a site at which points on river 
banks have been excessively filtered. The color-shaded map 
(Figure 10(a)) allows interpretation of the shape of the banks, so 
it has to be concluded that there has been no problem in the 
filtering. Meanwhile, the accentuated display of the 
monochrome shaded map on the background of the 
monochrome shaded point map ( 
Figure (b)) shows that ground data has been eliminated. From 
the result of the examination of the monochrome shaded point 
map, it can be concluded that “the filtering has been excessive 
and, thus, the point groups have to be retrieved using manual 
filtering.” 
(a) Color-shaded map (b) Monochrome shaded point map 
3.4 Combined Use of QC/QA Maps and Its Effect 
Figure 8. Examination of a forested area 
A monochrome shaded point map cannot be used for the 
examination of feature data in a forested area. At the same time, 
a color-shaded map cannot detect the elimination of data during 
excessive filtering. Therefore, we have developed a quality 
control method that uses a combination of the monochrome 
shaded point map and the color-shaded map. The purpose of 
this combined use is to compensate for the disadvantages of one 
with the other. 
(a) Color-shaded map (b) Monochrome shaded point map