Transcript Lecture 1: GIS In the Web Era

Lecture 1: GIS In the Web Era
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The Web and GIS
Web GIS origins and evolution
Web GIS concepts
Web GIS applications
The Web and GIS
The Internet, the Web, and the mobile Web
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Birth of the Internet: ARPANet --When ARPANET connected UCLA to Stanford, UC
Santa Barbara, and the University of Utah, there were three things that users could
do: log into a remote computer, print to a remote printer, and transfer files
between computers.
As ARPANET aged, it grew at a steady pace, constantly connecting more computers
and institutions, and adding new technologies along the way. In 1983, ARPANET
converted its old NCP( Network Control Protocol) to the newer and more universal
TCP/IP. This created what is known today as the Internet, since it allowed different
networks (ARPANET, NSFNET, CSNET, BITNET) to be interconnected. The TCP/IP
protocol is still used today.
The Internet did not gain popularity until 1990s. Before then, main services were
e-mail, Usenet News, file transfer, and Telnet. Complex to use, mainly for
professionals.
In 1990, Tim-Berners-Lee (“father of the Web”) at CERN (European Org. for
Nuclear Research) invented HTTP (Hypertext Transfer Protocol), HTML (Hypertext
Markup Language), and the URL (Uniform Resource Locator). He developed the
first Web server and a Web browser, naming his invention the World Wide Web.
• Internet: a massive network of networks that
connects millions of computers worldwide
using a number of protocols: HTTP, SMTP
(Simple Mail Transfer Protocol), FTP,
IRC(Internet Relay Chat), IM (instant
messaging), Telnet, and P2P(peer-to-peer).
• World Wide Web(WWW): a system of
interconnected hypertext documents and
programs that can be accessed via the Internet
primarily by using HTTP.
• The Web is still quickly expanding, from wired
into wireless (mobile Web).
GIS
• GIS is a system of computer hardware, software,
and procedures that capture, store, edit,
manipulate, analyze, and visualize geo-referenced
data.
• The first operational GIS (Canada G.I.S.- CGIS) was
developed in 1962 by Roger Tomlinson (“father of
GIS”) for land inventory and planning.
• GIS capabilities go beyond mapping. GIS offers a
rich set of analytical functions.
• The emergence of Web GIS is unlocking the power
of GIS to a wider audience.
Web GIS Origins and Evolution
Early Web GIS
• In 1993, the Xerox Corporation Palo Alto Research Center (PARC)
developed a web-based map viewer, marking the origin of Web GIS.
Users could use the map viewer in a web browser and click a link to
a function. The browser sends an HTTP request to the web server,
the server receives the request, performs mapping operations,
generates a new map, and returns it to the browser. The browser
displays the map as a map image.
• Early Web GIS examples:
- 1994, Canadian National Atlas Information Service
- 1995, Alexandria Digital Library
- 1995, National Geospatial Data Clearinghouse (by USGS)
- 1995, U.S. Census TIGER Mapping Service
- 1996, Mapquest.
Web GIS in the Web 2.0
• Web 2.0 was coined in 1999 to describe web sites that use
technology beyond the static pages of earlier web sites. It is closely
associated with Tim O'Reilly because of the O'Reilly Media Web 2.0
conference in 2004. Although Web 2.0 suggests a new version of
the World Wide Web, it does not refer to an update to any technical
specification, but rather to cumulative changes in the ways software
developers and end-users use the Web.
• A Web 2.0 site may allow users to interact and collaborate with
each other in a social media dialogue as creators of user-generated
content (UGC) in contrast to websites where people are limited to
the passive viewing of content. Examples of Web 2.0 include social
networking sites, blogs, wikis, video sharing sites, hosted
services, web applications, mashups.
• Upcoming Web 3.0: its most important features are the Semantic
Web and personalization. Web 3.0 is where "the computer is
generating new information", rather than human.
A tag cloud (a typical Web 2.0 phenomenon in itself)
presenting Web 2.0 themes.
ESRI product embodying Web 2.0
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Harnessing of collective intelligence and data.
-ArcGIS Server geospatial Web services (feature editing services, mashup capabilities) allow organizations to
collect and share geographic knowledge, promoting collaboration;
-ArcGIS.com (ArcGIS Online) provides a platform for sharing data, maps, and applications.
• Using the Web as a platform.
-ArcGIS Server: able to publish base maps, globes, and geo-processing functions as Web services.
-ArcGIS Online provides cloud-based software and services.
-Use Sass (Software as a service) and S+S (Software plus Service) approach.
• Mashup programming.
- A mashup, in web development, is a web page, or web application, that uses and combines data,
presentation or functionality from two or more sources to create new services.
-Integrate or mashup Web services from multiple agencies using ArcGIS REST API or lightweight ArcGIS
APIs for JavaScript, Adobe Flex, and MS Silverlight.
• Mobile solutions: Apple iOS (iphone, ipad), Google Android, Blackberry – retrieve data, view maps,
use analytical GIS models, post geospatial data.
• A rich user experience.
-Developers can create rich Web GIS applications with the use of ArcGIS APIs for JavaScript, Flex, and
Silverlight.
-ArcGIS Explorer: 2D, 3D virtual globe, geospatial patterns.
Explorer for Emergency Managers in Goochland County
• - ArcGIS Explorer Online: With ArcGIS Explorer Online, you can easily explore, visualize, and share
GIS information. Use it to directly access basemaps and other content. You can even use it to create
an interactive slideshow. ArcGIS Explorer is a free application that runs in a browser. It is built using
Microsoft Silverlight.
Web GIS Concept
Definition
• Web GIS started off as GIS running in Web browsers and has evolved into
Web GIS serving desktop and mobile clients.
• Web GIS is any GIS that uses Web technology to communicate between
components: server(identified by URL) and client (a browser, a desktop
application, or a mobile application). The communication is via HTTP. The
format of the response can be an HTML, binary image, XML(Extensible
Markup Language), or JSON(JavaScript Object Notation).
• The simplest architecture: 2-tier client-server (C-S) system. Server program
runs on the Web or in the cloud. C-S can be on one computer.
• Multi-tier system: 3 tier (including a data tier), >3 tiers in mashup Web
GIS.
• GeoWeb is not identical to WebGIS. GeoWeb is the merging of geospatial
information with non-geospatial information (e.g., Webpages, photos,
videos, and news). GeoWeb is related to the geotagging and geoparsing
research area of WebGIS.
Characteristics of Web GIS
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Global reach by HTTP.
Support a large number of users simultanuously: requires high performance and
scalability.
• Better cross-platform capability:
-Different Web browsers: IE, Firefox, G. Chrome for diverse OSs (Win, Linux, Mac OS,
iOS).
-Web GIS relying on HTML clients supports different operating systems(OSs).
-Web GIS relying in Java, .Net, and Flex can run on multiple platforms.
-However, Web GIS for mobile clients is far from being cross-platform b/c of the
diversity in mobile OSs and the incompatibility of mobile Web browsers.
• Easy to use for end users. “If I do not know how to use your site, it is your fault”.
• Unified system update.
• Diverse applications. Neogeopgarphy,("new geography“), is commonly applied to
the usage of geographical techniques and tools used for personal and community
activities or for utilization by a non-expert group of users.
Web GIS Applications
Functions
• Mapping/visualization and query (attribute or
spatial).
• Collaborative collection of geospatial
information. E.g., wikimapia, OpenStreetMap.
-- VGI (volunteered geographic information).
• Geospatial analysis: measurement, optimal
driving path, routing, pollution dispersion
modeling, retail site selection,…
Uses
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Web GIS as a new business model and a new type of commodity:
Location-specific advertising based on map mapping, e.g., Google Map.
SaaS business model: Web GIS can also be provided as a commodity. E.g., ESRI
Business Analyst Online (BAO).
Web GIS as an engaging and powerful tool for e-government. E.g.,
http://www.srcpa.org/ .
A new infrastructure for e-science: E-Science (or eScience) is computationally
intensive science that is carried out in highly distributed network environments, or
science that uses immense data sets that require grid computing (the federation of
computer resources from multiple administrative domains to reach a common
goal); Web GIS provides an infrastructure for geo-science research collaboration.
Web GIS in daily life: location-based service (LBS) supported by mobile Web, smart
phones and tablets. LBS include services to identify a location of a person or
object, such as discovering the nearest banking cash machine or the whereabouts
of a friend or employee. LBS include parcel tracking and vehicle tracking services.
LBS can include mobile commerce when taking the form of coupons or advertising
directed at customers based on their current location. They include personalized
weather services and even location-based games.