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  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-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 strategy

Client-side Strategies Server tasks Client tasks AnalysisDisplay 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

Real-time GIS

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

Combination and Hybrid Strategies

Applications Mass MarketServerSide Smaller, GIS SavvyClient-Side TransactionsHybrid 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 web/ web/ Goal  Provide information on contaminant sites available in GIS online Features  Address locator  Contaminant site GIS Viewer  Criteria query

Maryland SHA - Chart II 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 Goal  Provide Real Time Crime Reporting Information for DE Features  Enterprise Web Client/Server  ActiveX Map Viewer  GPS/Wireless Technologies

Real Estate Property Viewer Goal  Provide real estate property information on the Web Features  Gigabytes of data records  Simple user interface

TerraServer 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