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

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

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

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 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