WebGIS
Web & GIS ….WebGIS
• Access without purchasing proprietary
software
• Data directly from producer
• Emerging new market
The challenge of WebGIS
• Creating software systems that
work any desktop
WebGIS architectures
• Server-Side
• Client-Side
• Hybrid
Server-Side
• Definition: End users submit requests for
data and analysis to a web server. The
server processes the requests and returns
data or a solution to the remote client.
(Thin Client)
• Advantages
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High performance server
Eliminate large data sets being sent
More control
• Disadvantages
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Bandwidth
High performance client machines
Every request must be communicated
Server-side strategies
Server-side Strategies
Server-side
Strategies
Server
Client
tasks
tasks
Map
Display
browsing
Query
Analysis
Map
drawing
Client-Side
• Definition: End users can perform some data
manipulation and analysis locally on their own
machines. (Thick Client)
• Advantages
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Take advantage of powerful client machines
Greater control of data to the user
Reduced requests sent over the network
• Disadvantages
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Large of amounts of data and applets sent
Users may not have a powerful machine
Users may not have the training to employ the data and
analysis functions properly
Client-side strategy
Client-side Strategies
Client-side
Strategies
Server
Client
tasks
tasks
Analysis Display
Map
Map
drawing browsing
Query
Real-time GIS
• Variations on the client-side strategy can be
used
• Involves feeding data directly into the system
from sensors
• Real-time can used to:
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Monitor vehicle location or traffic conditions
Monitor weather and hydrological conditions
Track tagged animals in habitat monitoring
• Can deliver data across the Internet without
the need for dedicated cable, telephone, or
radio feeds
Real-time GIS
Variations on the client-side strategy
•
Add GIS functionality to Web
browsers
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The alternatives are to:
Download and permanently install a
"plug-in"
Build capabilities into existing GIS
software that runs on the client
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Variations on the client-side strategy
Combination and Hybrid Strategies
• Pure server-side and clientside strategies have distinct
limitations:
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Server-side strategies sensitive
to Internet bandwidth
Client-side strategies are
sensitive to the computational
power of the client
Hybrid
• Definition: Server and Client processes
combined to optimize performance and
meet special user needs.
• Better Matched Solutions for Computer
Capabilities
• Smart Task Assignments
Combination and Hybrid Strategies
Applications
• Mass Market
ServerSide
• Smaller, GIS Savvy
Client-Side
• Transactions
Maps on Demand
Hybrid
WebGIS trends
• Lower access cost
• Provide better customer service
• Shared data and GIS
functionality
• “Pay-for-use" mapping and GIS
services
GIS Vendors and Products
• Four Major GIS Vendors
ESRI
AutoDesk
Enterprise Information Solutions, Inc.
Intergraph
MapInfo
ESRI
• ArcView IMS
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Server-Side strategy
Server platform - Windows 95, 98, NT, Unix
Client software - JavaScript, Java, HTML,
Active X
Client platforms - All
Client-side data formats - GIF/JPEG images
Enterprise Information Solutions, Inc.
ESRI
• MapObjects IMS
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Hybrid strategy
Server platform - Windows 95, 98, NT
Client software - ArcExplorer, JavaScript, Java,
HTML, Active X
Client platforms - All
Client-side data formats - GIF/JPEG images,
ESRI shapefiles
Enterprise Information Solutions, Inc.
ESRI
• ArcIms
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Hybrid strategy
Server platform - Windows 98, NT, Unix
Client software - JavaScript, Java, HTML,
Active X
Client platforms - All
Client-side data formats - GIF/JPEG images,
ESRI shapefiles
Enterprise Information Solutions, Inc.
Intergraph
• Geo Media Web Map
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Hybrid strategy
Server platform - Windows NT
Client software - Plug-in for Active CGM, ASP,
VBScript, HTML, Active X
Client platforms - Windows 95, 98, NT
Client-side data formats - Active CGM
Enterprise Information Solutions, Inc.
MapInfo
• MapXtreme
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Hybrid strategy
Server platform - Windows NT, UNIX,
(MapXtreme Java)
Client software - ASP, VB Script, JavaScript,
HTML, Active X
Client platforms - All
Client-side data formats - As implemented by
developer
Enterprise Information Solutions, Inc.
AutoDesk
• MapGuide
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Hybrid strategy
Server platform
Client software - JavaScript, HTML
Client platforms - All
Client-side data formats - GIF/JPEG images
Enterprise Information Solutions, Inc.
Web and GIS Demonstration
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Environmental Navigator
Maryland SHA Chart II
Real Time Crime Reporting
Real Estate Property Viewer
TerraServer
Environmental Navigator
• http://sirb.awm.dnrec.state.de.us/en
web/
• Goal
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Provide information on contaminant
sites available in GIS online
• Features
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Address locator
Contaminant site GIS Viewer
Criteria query
Maryland SHA - Chart II
• http://www.sha.state.md.us
• Goal
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Provide traffic monitor information for
the State of Maryland
• Features
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From Legacy to Hot Java
Web, database, and GIS integration
Ad hoc reporting system
Real Time Crime Reporting
• http://www.citymaps.sacto.org
• Goal
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Provide Real Time Crime Reporting
Information for DE
• Features
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Enterprise Web Client/Server
ActiveX Map Viewer
GPS/Wireless Technologies
Real Estate Property Viewer
• http://www.webgis.net
• Goal
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Provide real estate property
information on the Web
• Features
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Gigabytes of data records
Simple user interface
TerraServer
• http://www.terraserver.microsoft.com
• Goal
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Provide Imagery for property
assessment, engineering, traffic
planning, personal mapping, etc.
• Features
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1m to 1km digital orthoquad imagery
Free imagery downloads
Site finder and lat/long information