USE IMAGE STREAMIN 
G TECHNOLOGIES TO PRESENT HIGH RESOLUTION 
IMAGES ON THE INTERNET 
Steven Y. Hu, Vincent Tao 
Geospatial Inf 
Department of Earth and Space 
'ormation and Communication Technology (GeoICT) Lab 
Science and Engineering 
York University 
Toronto, Ontario, Canada M3J 1P3 
Email: stevenhu@yorku.ca, Email: tao@yorku.ca 
  
Huayi Wu 
State Key Lab of Information Engineering for Surveying, 
d, Wuhan, 430079, P.R.China, 
Wuhan University, 129 Luoyu Roa 
Mapping and Remote Sensing (LIESMARS) 
Email: wuhuayi(@mail.liesmars.wtusm .edu.cn 
  
KEY WORDS: Internet/ Web, GIS, Mapping, Development, Image, 
ABSTRACT: 
Geospatial information services over the Internet become a technol 
and communication technology. One key 
challenge of high-resolution images is the 
download the whole image, which is of hundreds Megabytes 
implementation of a special browser (GeoServNet, 
the best performance, a lot of optimizations should be 
h means it will always process images near the viewers’ 
scene whic 
hich are viewed again, the data c 
to cache and deliver the images w 
from the server. The system has been tested in di 
1. Introduction 
Geospatial information services over the Internet become à 
technological trend driven by the innovations of geospatial 
information and communication technology. There are few 
commercial systems emerged in late two years, such as two 
dimensional systems, Maplnfo, MapGuide, etc. and three 
dimensional systems, TerraExplorer, EarthViewer3D and G- 
Vista etc. Until now, GeoServNet (GSN), developed by the 
GeolCT Lab, York University, is the only advanced Internet- 
based geospatial information system (GIS) having the 
capability of 2D and 3D analysis in the world. GeoServNet 
serves as a web-based GlIService engine, offering both 3D and 
2D geospatial exploration capabilities to access heterogeneous 
spatial data sets over a distributed environment. It integrates 
vectors, images, DEMs, 3D models, multimedia dada, 
documents and databases seamlessly in an open, secure, 
scalable and fast fashion. The system will handle several key 
data: vectors, images and DEMs. It is apparent that the 
challenge work is the large data set and the limited computer 
and network resources. 
Currently, there are two development directions for Internet- 
based web-mapping systems. One is traditional client/server 
based web-mapping system and the other is web service based 
web-mapping system. The latter uses a common protocol to 
provide different services to the users on the Internet. The most 
famous web services system is standardized by OGC (Open 
GIS Consortium). Even though it is a trend for developing web- 
services technology, the low 
problem for this type of 
system by web 
mapping 
remains a big 
performance 
issue is how to present high resolution images wit 
ir huge sizes of data even after the finest image compressi 
www.geoict.net) for processing | 
done. It implements a level of detail (LOD) 
  
Resolution, Software, Web based 
en by the innovations of geospatial information 
h high performance. The biggest 
on. It is impossible that we 
after compression, then display it This paper presents the 
arge images over the Internet. In order to gain 
algorithm to display images in 2D 
point. It also implements an image pool and streaming algorithm 
an be directly retrieved from the cache instead of request it again 
ogical trend driv 
fferent bandwidth networks from low speed to high speed. 
applications. Due to the web services are negative systems and 
their protocols are based on XML language, it will be very 
difficult to make an application with the streaming technologies 
which are the most useful technologies to speed up the data 
exchanges within Internet applications. That is why most of 
web-mapping systems still keep the traditional client/server 
architecture. By definition of itself data structure and transform 
protocol, this type of application can be designed being much 
more fancy and can gain higher performance than web services 
systems. Recently, most commercial web-mapping systems 
mentioned in abstract are not web services based and they have 
their own system architectures and internal data formats and 
they are not compatible to each other. Additionally, high- 
quality images have become a mission critical component of 
professional techniques and operating procedures in most fields 
of academic and corporate endeavor. Affected arenas include 
but are by no means limited to: education, medicine, criminal 
justice, defense, commerce, entertainment and more. The 
images has increased 
ability to capture high-quality 
dramatically in the last decade and has, ir 
ability to share and make use of the level of resolution now 
commonly achievable. Digital cameras now surpass film in 
capture quality and are approaching film in annual exposures 
with over 9.1 billion exposures in 2000 to 29.5 billion expected 
in 2005 (IDC, March 2000). Multi-mega-pixel cameras now 
rage costs have become a major 
and Web-based presentation à 
Evolving at an equally 
and security-related imaging 
megabytes of data through 
many hours now capturé 
1 fact, surpassed the 
capture images so large that sto 
implementation consideration 
daunting technical challenge. 
unprecedented pace, scientific 
systems previously capturing 
complicated manual processes over 
gigabytes of data automatically in minutes. 
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