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International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences, Vol XXXV, Part B7. Istanbul 2004 
  
  
  
  
for When there is no GCPs, the errors in plane is about 10m, and obtained as much as possible, it is a right method to develop 
qd s the error in the height is less than 10m. block adjustment based on RPC model to reduce the amount of 
(ith the GCPs by the greatest extent. 
use 3.4 The block adjustment test and the result Over 20 schemes of GCP distribution are design for block 
ted adjustment. The schemes and their results are listed in table 4. 
out There is a great challenge in field survey because of the 
1). particularity of the project area. Although the GCPs are 
No. The GCPs schemes RMS of RMS ORG: RMS SÉCP E 
IP(pixel) | RMSx | RMSy | RMSz | total | RMSx RMSy | RMSz | Total 
4 1 All 41 GCPs 0.276 0.474 0.561 0.235 0.771 
2 All SM I GCPs 0.311 0.486 0.658 | 0.184 0.838 0.564 0.619 1.170 1.439 
3 All SM II GCPs 0.307 0.575 0.456 | 0.286 0.788 0.515 0.711 0.864 1.232 
4 All SM 111 GCPs 0.306 0.373 0.527 | 0.220 0.682 0.648 0.731 1.290 1.618 
5 All SM I & SM III GCPs 0.292 0.419 0.584 | 0.197 0.745 0.659 0.614 0.667 1.12] 
6 AlI SM I & SM II GCPs 0.290 0.529 0.570 | 0.231 0.817 0.418 0.696 0.580 | 0.998 
7 All SM II & SM III GCPs .287 0.417 0.522 | 0.245 0.745 0.639 0.755 1.251 1.594 
9 8 4 SM I GCPs & 2 SM III GCPs 322 0.449 0.169 | 0.204 0.521 0.552 1.029 0.736 1.381 
& 9 6 SM I GCPs & 2 SM III GCPs 0.318 0.457 0.494 | 0.199 0.702 0.566 0.940 0.792 1.353 
» I0 | AIISMIGCPs & 2 SM III GCPs 0.307 0.458 0.626 | 0.177 0.795 0.554 0.678 0.915 1.266 
E: [1 All SM II GCPs & 2 SM I GCPs 0.306 0.558 0.485 | 0.294 0.795 0.495 0.731 0.576 1.054 
É 12 | All SM II GCPs & 2 SM III GCPs 0.303 0.548 0.455 | 0.274 0.764 0.535 0.757 0.887 1.284 
! 13 4 SMIGCPs 0.326 0.511 0.203 | 0.125 0.564 0.618 1.026 1.423 1.860 
14 6 SM I GCPs 0.321 0.484 0.567 | 0.149 0.760 0.742 0.898 1.557 1.945 
15 1 GCP(middle) 0.333 0.016 0.012 | 0.001 0.020 0.951 0.733 0.956 1.535 
16 2 GCPs(one in each end) 0.330 0.304 0.127 0.256 0.417 0.752 0.818 0.840 1.393 
17 4 GCPs(2 GCPs each end) 0.327 0.360 0.086 | 0.230 0.436 0.602 1.039 0.748 1.415 
18 6 GCPs(2 GCPs each SM) 0.322 0.419 0.464 | 0.208 0.659 0.558 0.774 0.659 1.160 
19 7 GCPs(1 middle, 2 each SM) 0.32% 0.472 0.421 0.283 0.693 0.556 0.764 0.517 1.076 
20 12 GCPs(4 each SM) 0.314 0.409 0.433 | 0.242 0.643 0.582 0.777 0.510 1.097 
  
and The block adjustment tests and the results have shown that: Max. Min Ave. | RMS 
e io ® The Ikonos accuracy is stabilization in anyone X 2.4 17 0.38 | +0.83 
control scheme. Y 2.6 23 -0.43 | +0.97 
J e The location of the GCP is at will, but it must be on S £1.28 
rom 
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
Note: SM----Stereo Model; IP----Image point; GCP----Ground Control Point; CP----Check Point. 
Table 4 The GCPs schemes and their result of the block adjustment 
the object which its image is clear and the character is 
distinctness. 
® The accuracy can be improved greatly even only one 
GCP, 
€ The RMS of the ground point is about +1.5m when 
the interval of the GCPs is 15km, and +2.0m at 20km. The 
longer the interval of GCPs, the worse the accuracy of the 
height. 
® The higher accuracy can be reached when 2 GCPs 
exist along south-north in each stereo images, but the 
accuracy is improved little with more GCPs. 
® The RMS of production produced with Ikonos image 
in Himalayas has reached +0.945m in plane, +0.510m in 
height, and +1.076m in total. The RMS of image point is 
+0.3 pixels. 
3.5 The accuracy of Digital Line Graph(DLG) 
The accuracy of the plane and the height of the DLG produced 
with Ikonos image was examined on the spot. The errors in the 
plane and the height were calculated by comparison between 
the DLG and the survey data (table 5, table 6, table 7). 
1047 
  
  
  
  
  
  
  
  
  
  
  
Table 5 The plane accuracy of the DLG(meters) 
  
RMS 
+1.14 
Max. Min. Ave. 
4.0 -3.2 0.40 
  
  
  
  
  
  
  
Table 6 The height accuracy of the DLG(meters) 
  
Max. Min. Ave. RMS 
1.9 -1.6 0.26 0.64 
  
  
  
  
  
  
  
Table 7 The accuracy of the height point >meters 
It has shown from table 5 to table 7 that the accuracy of the 
DLG has satisfied the specification of the scale of 1:2000. 
3.6 The accuracy of the Digital Elevation Model(DEM) 
The DEM was produced from the Ikonos stereo model and its 
interval was 5m. The height of the check point in DEM was 
interpolated. The errors of the DEM was calculated by the 
comparison of difference between the DEM and the survey 
(table 8).