International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences, Vol XXXV, Part B4. Istanbul 2004 Intel 
interface which will be used to accept image objects coming 4.4. Image Streaming Transmission Module eni 
diffe 
from image streaming transmission module. 
This module as shown in Figure 4.7 links the GSN client and 
Xp ND ME GSN server. 
a Check request queue : à; * : Tabl 
There is one important thing needed to do before save image 
: objects to image pool which is to call image pool memory 
management method to maintain the footprint of the pool. 
Otherwise, system will crash after the pool burns all the 
  
  
  
  
  
  
  
  
  
  
     
    
  
  
  
  
  
  
  
  
  
  
         
  
  
  
  
   
     
    
  
  
  
    
  
  
  
  
  
  
  
  
  
   
  
  
   
  
   
  
   
    
       
  
  
  
  
  
  
  
  
  
  
  
  
  
  
etna cono memory of users’ machine. Figure 4.6 is its flow chart of Win: 
Calculate image objects in the algorithm. size 
map bounding box from Np iet EE 
display module Check image 5 640) 
| obiect queue ‘ 
5122 
= : ; x 
For all image objects | 4003 
320% 
250% 
200% 
Request the image object bs The 
di IR from server 3 ans 
Generate image Send image object to (ans 
. . . ag 
object from draw image object > EN 
overview map module fans 
becar 
su small 
Send image object band: 
request to image 422K 
streaming » E 5 the 1 
transmission Get request from image pool and save 5 125K 
image objects to it and check pool size; i that n 
Draw image obiect to users’ screen. d data 1 
Figure 4.5. Flow Chart — Image Pool they 
Figure 4.6. Image Streaming Transmission Module on the 
4.3. Draw image object module 
The essential issue is to make sure the final image is 
seamless. For this reason, every image object (tile) is 
assigned a bounding box. Where to put the tile is decided by 
its bounding box and the screens bounding box. 
Based 
more 
respoi 
Get request from \ any d 
image pool and sav not be 
image objects to it fancv 
Pu and check pool size are Fl 
C= Communicate The la 
with server in this 
; ue 3D 1 
Draw image Thread n 
: ; Draw becom 
object to users imaie 
: d be to | 
screen object 
techno 
By a 
Se à umeros i System 
Figure 4.7. Image Streaming Transmission Module ks d 
Suppor 
: ; - ead Set ser 
operations on GSN Image Viewer. The two criteria items fe a 
; : : ^ ature 
5. A Test Result used to evaluate are image amount and image quality of data 
transmitted from server to client. Experiments showed that ' 
Constrained by the available hardware resources (network the response time is 0 for any operation due to a high quality C 
bandwidth, machines’ performance), the GSN can not be overview image and image pool was always being able to : 
; ; Y : ; OM : ; ; ; CC 
tested on a real various simulating users working show user some thing ignoring the show's quality. The image 
; = . . . ~ . . , Re 
environment. The alternative approach to do this test 1s to data transferred were very depending on the viewer 5 e 
count the transferred data size while doing different windows size. Table 5.1 shows the relationship between 
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