The geodata-rich society
ESRI president Jack Dangermond recently predicted that the supply of satellite and aerial imagery will increase by two folds in the next few years. Availability will also increase greatly, via Web portals and online GIS services. This is all part of what Dangermond describes as a "geodata-rich society" that will have access to more geospatial information of all kinds, including, in addition to imagery, GPS/location data, geo-demographic data, and data from real-time monitoring . The Internet is already the 'foundation medium' to access, link and use all these data.
Satellite imagery and remote sensing are quickly entering the mainstream. Today, satellite imagery data are abundantly available from multiple sources, including companies such as Space Imaging http://www.spaceimaging.com/, Orbimage http://orbimage.com/, DigitalGlobe http://digitalglobe.com/, GlobeXplorer http://www.globexplorer.com/, Spot Image http://www.spot.com/, ImageSat International http://www.imagesatintl.com/, and EarthSat (http://www.earthsat.com/ – an MDA company), and are used in hundred of applications. But thanks to online consumer services like Terraserver http://www.terraserver.com/, Google Earth, and Microsoft Virtual Earth (see 'Background' section above), satellite imagery has also been made familiar and accessible to millions of people.
The wikification of GIS, maps and satellite imagery/aerial photography: imaging and geospatial information for the wide masses
There is no doubt the different online consumer geoinformatics services that have been presented in the 'Background' section of this article, including the different geographic search interfaces from major Web search engine providers, have significantly contributed (in record time) to raising the general public interest in geography and satellite imagery. As millions of people start "playing" with these new online "gadgets" or "toys" from Google and Microsoft, many of them will soon start thinking about becoming active participants, sharing information and collaborating online (notions that have been rightly associated with the Web for quite a long time), rather than just being satisfied with a passive information consumer/viewer role. (The reader should note that it has been estimated that about 800 million persons are online today worldwide .)
However, although Google Maps API (and similar API offerings from other providers) enables users to deeply customize the standard provider's interface (Google Maps), and to create their own custom annotated maps (custom applications based on Google Maps), such APIs remain difficult for the non-expert, average user to exploit. This author expects the technology to further evolve to enable the average Web user to share geospatial information, to customize, annotate and publish his/her own online maps and related Web applications, and to collaborate with other users/online communities within an online customizable and collaborative mapping environment, all without the need for any prior programming knowledge or expertise. (Such user-friendly applications that do not require end-users to have any programming expertise to use them can also be built using the existing APIs.)
The current 'wiki' concept is not far from this vision. A wiki (from Hawaiian wiki, to hurry, swift) is a collaborative Web site whose content can be edited by anyone who has access to it . Perhaps the best example of a wiki in action today is 'Wikipedia – The Free Encyclopedia' (see the 'wiki' entry in Wikipedia at http://en.wikipedia.org/wiki/Wiki). A related Web information sharing technology is the 'blog'. A blog (WeBLOG) is a Web site that contains dated entries in reverse chronological order (most recent first) about a particular topic. Functioning as an online journal, blogs can be written by one person or a group of contributors. Entries contain commentary and links to other Web sites, and images as well as a search facility may also be included ( – see the 'blog' entry in Wikipedia at http://en.wikipedia.org/wiki/Blog).
Wikis, and in particular Wikipedia, have grown very popular in recent months and years . Wikis represent a promising principle that can significantly transform the Internet information age. Special conferences have been and are being organized to discuss this interesting Web phenomenon of wikis; for example, Wikimania 2005, the First International Wikimedia Conference, 4–8 August 2005, Frankfurt am Main, Germany http://wikimania.wikimedia.org/wiki/Main_Page, and the ACM (Association for Computing Machinery)-sponsored WikiSym 2005, the 2005 International Symposium on Wikis, 17–18 October 2005, San Diego, California, USA http://www.wikisym.org/.
Along the same lines, it is not difficult to imagine the development in the very near future of 'geowikis', 'mapwikis', geo-enabled blogs, 'mapblogs' (imagine, for example, people with an Internet-connected, GPS-enabled mobile device wanting to blog their movements, and share their activity spaces and geo-referenced news with other online users for various purposes), and even geo-enabled, mappable Web/RSS feeds and map feeds (see the Smugmug KML photo feed example mentioned in the 'Background' section above). In fact some early geowiki examples have already found their way on the Web; see, for example, http://www.wikyblog.com/Map/Guest/Home, http://www.geowiki.com/, and also worldKit GeoWiki, a publicly editable map application http://brainoff.com/worldkit/doc/geowiki.php (a simple online demo of worldKit GeoWiki to which anyone can add their own data is available at http://brainoff.com/worldkit/geowiki/).
Another example is the Katrina Information Map http://scipionus.com/, which was built using Google Maps . Katrina Information Map was conceived for use by people affected by Hurricane Katrina (August 2005) and their relatives who have, or are trying to find, information about the status of specific locations affected by the storm and its aftermath. Users having information about the status of an area that is not yet on the map can easily contribute to the map by adding/appending their information to it. (Readers interested in Hurricane Katrina's online maps and imagery in general might also find the following two sites useful: http://www.esri.com/news/pressroom/hurricanemaps.html, http://ngs.woc.noaa.gov/katrina/, http://www.theregister.co.uk/2005/09/07/google_maps_katrina/ and http://msnbc.msn.com/apps/ve/katrina.htm.)
The possibilities and potentials are endless. This is what this author calls the ultimate "wikification" of GIS, maps and satellite imagery/aerial photography. If the majestic Tate Museum in London is currently posting captions from its visitors next to its greatest works of art , why shouldn't online maps (even those from very reputable sources like the National Geographic Society) allow a similar approach?!
Associated individual privacy, national security, data confidentiality, and copyrights/digital rights management issues
As geospatial technology progresses and becomes more readily available to the wide masses around the world who are connected to the Internet, the interrelated issues of GIS and map data confidentiality/individual privacy, and even national security start to surface, calling for further examination of, and research into these delicate aspects of Internet GIS and Web maps [5, 17–22].
For example, in public health worldwide, any public identification of an individual's health status and residence, regardless of level of contagion or risk, is usually prohibited with very few exceptions, e.g., Megan's Law in the US, which allows the release of residential information on registered child sex offenders to the public by local government [17, 23]. In fact, thanks to the latter law, we have a service like the Georgia Sex Offender Maps http://www.georgia-sex-offenders.com/maps/, which was built using Google Maps API. SARS (Severe Acute Respiratory Syndrome) mapping in Hong Kong in 2003 using disaggregate case data at individual building level in near real time was another noticeable exception to this well-established public health confidentiality rule, and also a unique and rare GIS opportunity that resulted in some very comprehensive public Internet mapping services .
It is noteworthy that Google Maps API terms and conditions http://www.google.com/apis/maps/signup.html state, "There are some uses of the API that we just don't want to see. For instance, we do not want to see maps that identify the places to buy illegal drugs in a city, or any similar illegal activity. We also want to respect people's privacy, so the API should not be used to identify private information about private individuals."
On another level, following the September 2001 terrorist events in the US, many federal and local spatial databases, e.g., "critical infrastructure" spatial data, were assessed by their holding agencies as a potential liability to national security and withdrawn from the Internet or public dissemination. The current concern is to find an appropriate balance between public access to spatial information and protection of information considered a priority for national security [17, 23].
But despite all these undeniable, legitimate and real concerns about Internet GIS and map data privacy and confidentiality, many of the doubts and misgivings that are raised concerning these aspects of Internet GIS seem to be ill founded, or at least exaggerated. Entchev  has wisely stated, "Let us not cripple the GIS system to meet some vague privacy perceptions".
Another thorny Internet GIS issue that needs to be addressed is that of data and map copyrights. Conner  has rightly described online maps as a copyright minefield. Copyrighted geo-data and maps are usually more difficult and expensive to acquire and use.
But as geo-data become more important in everything from blogs through mobile phones to finding lost people, free maps could make more and more of a difference . However, someone needs to pay the bill for such "free" maps, and so finding sustainable commercial models for adoption by online geo-data and Web map providers is becoming of prime importance these days . Examples of such commercial models include ad-sponsored map services, and low-cost, added-value paid services supporting the free service like Google Earth plus http://earth.google.com/earth_plus.html and Google Earth Pro http://earth.google.com/earth_pro.html. Microsoft also provides an alternative ad-supported, but still free, "commercialized" version of their MSN Virtual Earth Map Control for commercial Web sites .
The Open Geospatial Consortium's (OGC) work on Geospatial Digital Rights Management (GeoDRM) is also poised to become an important enabler in the context of geo-data and map copyrights . A great deal of work has already been done in the area of data ownership and rights management for the online e-book, video and music industries, with some mature working solutions already in existence from companies like Macrovision http://www.macrovision.com/, Microsoft (http://www.microsoft.com/windows/windowsmedia/drm/default.aspx and http://www.microsoft.com/windows/ie/downloads/addon/rm.mspx) and Adobe https://aractivate.adobe.com/. Such developments are of interest to the geospatial community in that many geospatial data providers need to control or track who has access to their data and how the data are used. The lack of a GeoDRM capability has been identified as a major barrier to the broader adoption of Web-based geospatial technologies. The mission of OGC GeoDRM Working Group is to coordinate and mature the development and validation of work being done on digital rights management for the geospatial community .