various 33 | out of segment network within segment network
— | #4 — '
id images | | 30 |
nl | 20 FF
8.9 | 10 |
wl | GHEE NA To TL
1.69 Sparcl0 ^ Sparc20 Sparcl0 sparc2 sparc20 Macintosh DOS/V DOS/V
" (à) (b) (o) (d) (o) (PowerPC) (Win95) (Win3.1)
0.76
2.36
— [] time for 12 thumbnail ga time for detailed image
e mea- images(124KB in JPEG) (27KB in JPEG)
ed md Figure 7 Expanded and displayed time of images on
eval various client machines
he sum
ita for- Win95 machine is attributed to the large difference of the net-
e mea- work performance. Figure 7 shows the comparison of the
etwork | time for thumbnail images to be expanded and displayed with
nt and | the time for the selected detailed image on various client ma-
verage chines. The influence of the network load on the total time
». The for images to be displayed on the screen of client machines is
1viron- very critical as seen in Figure 7. Since the ratio of the retriev-
Real ing time to the total time for images to be expanded and dis- — "BERE MEE.
aration
being
s from
M detis
Figure 8 Example of layout of 12 thumbnail images on the
window
v7 workstation might be acceptable in practical use. On the other
Le i hand, WWW browser on the personal computers seems to be
rather poor for expansion and displaying thumbnail images
and detailed images. Figure 7 shows the window for end-user
to enter retrieval conditions . We have tentatively selected
some items such as date, path, row, sensor's name and quality
of the image ,i.e., the portion of clouds to the whole satellite
image. Example of the layout of 12 thumbnail images on X-
Window of the workstation is shown in Figure 8 .
3. CONCLUSION
Preliminary satellite data retrieval system was constructed
on WWW server workstation. It was manifested that the oper-
rement üpure ability for end-user was fairly good because of adopting
WWW browser's graphical user interface. Measured real time
Iwan played is considerably small, the measured real time mostly for thumbnail or detailed images to be transmitted on the net-
twork | depends on the network load. The total time for 12 thumbnail work , expanded and displayed on the display holds accep-
le and images to be transmitted and displayed on the display of the tance in practical use.
153
International Archives of Photogrammetry and Remote Sensing. Vol. XXXI, Part B1. Vienna 1996
