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Introduction

Introduction. GIS was originally the preserve of large (mainframe) computers, but in the 1990s it became feasible on desktop PCs. The growth of the World Wide Web in the 1990s provided mass access to the Internet. It made sense for these two technologies to merge to create web-based GIS.

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Introduction

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  1. Introduction • GIS was originally the preserve of large (mainframe) computers, but in the 1990s it became feasible on desktop PCs. • The growth of the World Wide Web in the 1990s provided mass access to the Internet. • It made sense for these two technologies to merge to create web-based GIS. • GIS and the Internet also permit the expansion of Location Based Services (LBS). • Today we will look at GIS and the Internet.

  2. History Of The Internet • The Internet can be traced back to ARPANET in 1969. • It really took off in the 1980s, but still entailed a steep learning curve. • The World Wide Web developed by Tim Berners Lee in 1991 and user-friendly web browsers such as NCSA Mosaic changed all that.

  3. Web Technology • Web pages are basically text files with embedded HTML tags. • Early pages were static, but various technologies developed to make them more dynamic. • These technologies scould be either server-side (e.g. ASP or CGI) or client-side (e.g. Java applets). • Web 2.0 allows end-users to add their own content without programming skills (e.g. blogs, wikis, social networking)

  4. Standards • Standards are necessary to permit communication between different platforms. • Important standards bodies include: • W3C (World Wide Web Consortium) • HTML4, HTML5, XML, XHTML • OGC (Open Geospatial Consortium) • GML, WMS, WCS, WFS • FGDC (Federal Geospatial Data Consortium) • NSDI • Other • NSS (ISDI) • EU (INSPIRE)

  5. Web-Based Mapping • Degrees of complexity: • Static maps • Dynamic maps • Simple interactive maps • User-specified themes • User-added content • Web-based GIS

  6. Issues For Developers • Server-side or client-side • Accommodate local data • Data protection • Live data • Database interaction (attribute data) • Database interaction (spatial data) • Multiple sources • Scalability • Functionality • Browser compatibility

  7. Neogeography • Web sites such as Google Earth and Google Maps have opened up web map creation to the ‘general public’. • This has many positives: heightened awareness of the importance of space; ability to tap into a vast ‘knowledge database’; can combine oformation for diverse sources to create mashups (e.g. http://www.healthmap.org/) • Also some negatives: loss of accuracy; cluttering by trivia; ownership issues.

  8. Free Software • The internet allows programmers to cooperate on projects – free software movement. • Two meanings of free: • Gratis (no charge) – e.g. ArcReader • Libre (open source) – e.g. Linux • Linux/GNU: Richard Stallman (GNU), Linus Torvalds • Other examples: Apache, OpenOffice.org, R, MySQL, PostGreSQL, Python, Perl, PHP, Moodle

  9. Open-Source GIS • Desktop GIS: • GRASS (Geographic Resources Analysis Support System). Traditionally UNIX-only but now available for Windows. • Quantum GIS (QGIS) • Web-Based GIS: • Can be assembled from a variety of open-source tools: e.g. Firefox, Apache, UMN Mapserver, GeoServer, MySQL, PostgreSQL/PostGIS, GDAL/OGR, PROJ.4, R and R-spatial, GRASS, Zope, Python.

  10. Applications • Internet web-mapping • Intranet web-mapping • Geoportals • Application service providers • Location based services

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