webgis. web & gis ….webgis access without purchasing proprietary software data directly from...
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Web & GIS ….WebGIS
• Access without purchasing proprietary software
• Data directly from producer • Emerging new market
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 High performance server Eliminate large data sets being sent More control
• Disadvantages Bandwidth High performance client machines Every request must be communicated
Server-side Strategies
Server tasks
Client tasks
Map browsing
Display
Query
Analysis
Map drawing
Server-side Strategies
Client-Side
• Definition: End users can perform some data manipulation and analysis locally on their own machines. (Thick Client)
• Advantages Take advantage of powerful client machines Greater control of data to the user Reduced requests sent over the network
• Disadvantages 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 Strategies
Server tasks
Client tasks
Analysis Display
Map drawing
Map browsing
Query
Client-side Strategies
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:
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
• Add GIS functionality to Web browsers
• The alternatives are to: Download and permanently install a
"plug-in" Build capabilities into existing GIS
software that runs on the client
Variations on the client-side strategy
Combination and Hybrid Strategies
• Pure server-side and client-side strategies have distinct limitations: 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
Applications
• Mass Market ServerSide
• Smaller, GIS Savvy Client-Side
• Transactions Hybrid
Maps on Demand
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 Intergraph
AutoDesk MapInfo
Enterprise Information Solutions, Inc.
ESRI
• ArcView IMS 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 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 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 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 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 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
• Environmental Navigator
• Maryland SHA Chart II
• Real Time Crime Reporting
• Real Estate Property Viewer
• TerraServer
Environmental Navigator
• http://sirb.awm.dnrec.state.de.us/enweb/• Goal
Provide information on contaminant sites available in GIS online
• Features Address locator Contaminant site GIS Viewer Criteria query
Maryland SHA - Chart II
• http://www.sha.state.md.us• Goal
Provide traffic monitor information for the State of Maryland
• Features From Legacy to Hot Java Web, database, and GIS integration Ad hoc reporting system
Real Time Crime Reporting
• http://www.citymaps.sacto.org• Goal
Provide Real Time Crime Reporting Information for DE
• Features Enterprise Web Client/Server ActiveX Map Viewer GPS/Wireless Technologies
Real Estate Property Viewer
• http://www.webgis.net• Goal
Provide real estate property information on the Web
• Features Gigabytes of data records Simple user interface
TerraServer
• http://www.terraserver.microsoft.com• Goal
Provide Imagery for property assessment, engineering, traffic planning, personal mapping, etc.
• Features 1m to 1km digital orthoquad imagery Free imagery downloads Site finder and lat/long information