CS 128/ES 228 - Lecture 14b1 Maps and GIS’s on the Internet.

CS 128/ES 228 - Lecture 14b 1

Maps and GIS’s on the Internet


Fundamental Questions

Who has the maps?

Who has the data?

Who does the computation?


The simplest model Post a map

No different than posting a photo of your pet.

Post a series of linked maps No different that posting a photo album

of your pets.

Some Dull Maps


A More Sophisticated Model

Computer scientists often speak of a client-server model.

In this model, one computer (the server) answers questions posed by another (the client)


Examples of Client-Server

Google

Amazon.com

Actually, most web sites

3D map of world wide web from

www.opte.org


A Client-Server GIS Zillow – A Real Estate GIS

At first Zillow just connected home locations to the local tax rolls so that valuations became known

Then it combined with map servers to display by neighborhood

Now it is branching into the buy-sell arena

Zillow


Limitations of Zillow Not all areas

well mapped Geocoding is

imperfect Tax rolls are

inconsistent

Zillow does NO computation besides map focus


Servers that “compute” Mapquest will produce a page for you

that has never been viewed by anyone else in the history of the world!


GMaps Pedometer

Draw your running routes

View it!


ArcView IMS

Internet map server connected to Arc software

Capabilities Deliver dynamic maps (and DATA) through

the web Restrict user interface to something more

appropriate than ArcView Bring modern web technology into GIS

world


Example 1 – Reuters AlertNet

Series of GIS layers (world-wide) connected to an index (menu) featuring areas of interest to humanitarian/relief workers/agencies

AlertNet


Greenwood County Classic ARC-like interface

Visual BASIC.Net back end (also uses ActiveX)

“Lightweight” GIS – designed to load and compute quickly

Greenwood


San Francisco Prospector

Business information database

Extensive queries

Aerial photos

Access to other databases

www.sfprospector.com


What if we make the user compute?

Google Earth

•Free application that runs under most operating systems

•Interfaces maps and satellite imagery with databases


Google Earth Comes in many versions

Basic versions are free Enhanced versions cost modest amounts Part of a much larger suite of web-compatible

software Provides an applications programmer

interface (API) so that you can customize an application (GIS)


Concerns for GIS/Maps on the Internet

How much to restrict user interface? Who is the audience? What are the copyright issues? What are the privacy issues?

What technology to use? Support all browsers or just some? Programming language or just

scripting?


More Concerns... Hosting/serving issues

Who hosts? Data Security?

• Are on-line updates permitted or only queries?

Capacity? Scalability?

Develop on-line or “port” upon completion?

CS 128/ES 228 - Lecture 14b1 Maps and GIS’s on the Internet.

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