2004 International Archives of the Photogrammetry, Remote S ensing
and Spatial Information Sciences, Vol XXXV , Part B4. Istanbul 2004
| are
Figure 4.1 is the improved GSN client structure which includes
all the modules and their processing flow. *Add Image Object
elt to...” mean that Image Transmission Module will add Image
ei Objects that it gets from server to both Image Pool Module and
resi Draw Image Object Module. “Return image from pool
‚ine immediately” means that Image Pool Module will send Image
ined Objects back to Display Module from pool if they are available
m in the pool or from overview map if they are not available. And
x in then, if users’ requested Image Objects are not in the pool, it
uttam will forward users' requests to Image Transmission Module.
nos “Transmit required [Image Objects from server” are used for
nally, transferring Image Objects between GSN client and GSN (A) (B)
quest server. Its implementation can be either single thread or multi- Figure 4.2. Zoom In Operation: (A), (B)
table: threads. 2
ed by ; Figure 4.2 shows the algorithm of GSN display module. From
pothly 41. Display Module it, it will be very easy to conclude that the response time of
'es re- display module to users’ operation i related wi y
m The display module is the interfaces between GSN ren haie E Brei entere lied with users
system and users. It processes all operations of both
mouse and keyboard from users and then responses or Figure 4.3 is the flow chart of its aleorithm
presents with related results to them. : :
client. ES
es and < Zoonrin ly Wait for users
ty but e Zoom Out Y
e Smooth Zoom Process Users’ operations
e Pan Y
users’ e run fe Full EXC: Calculate the map area
g map : Toggle Legend (bounding box) showing to
h map * [Identify » users
e Show Attribute Table Y
* Find Feature :
: RUIN M. Get data from image pool
quests, * Toggle Overview Map
* JD View
e 2DFly :
paper, e Stop Draw map on the
ssist af ® Refresh users’ screen
* Measure Distance
* Hyperlink Figure 4.3. Flow Chart — Display Map
nd gets
t [Image
ORES RR PR
eon
0880053000808
e
e
x
e.
ea eee
® >»
e =»
e
e
- c Map pool:
e # ate »
D: data gotten
e: from server
i before
e ^
e ©
e
pd F SeNE 4 | Display
Image x" Image transmission es d V^ | module
Streaming Sew e+ Draw
Transmission es e|. image
e: : .
à 5 e|. object
e i e
e s e
3 Overview es :
9 : Map e *:
e e:
es ®
e : e
EET ETT ACER »*2 e.t
969090e600000000009000000000005?
Figure 4.4. Image Pool
42, Image Pool Module dashed lines in Figure 4.4. Figure 4.5 is the flow chart of
image pool. It is a thread. There is a queue in image pool. It
The pool will process users’ request, store images loaded is used to communicate with other modules. There is also a
from server and manage pool. Image pool is showed within
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