Virtual Globes in the Classroom
For teaching spatial thinking, Virtual Globes offer tremendous opportunities, and it can be expected that they will greatly influence how a new generation will perceive space and geographical processes. To help elicit the educational potential of Virtual Globes, this review explores their use as teaching tools and introduces a list of currently available Virtual Globes.
The goal of this review is to help educators digest a large amount of information in light of a tremendously rapidly changing technology. We understand that new versions of Virtual Globes are published continually, and that this overview can only be a beginning for those who want to explore the topic. We encourage the reader to look beyond technical details and consider the greater implications Virtual Globes will have for teaching spatial concepts and analysis.
With our overview of Virtual Globe applications, we do not endorse any particular product. We chose to review particular globes because of their current online presence and potential for in-class use. In addition to those applications mentioned in the list, the text also refers to applications and companies that have announced releases of new versions but that are currently unavailable.
For readers who are new to this topic, we have collected screenshots of a number of applications to quickly introduce Virtual Globes without the need for downloading an application or leaving this website.
Nuernberger, Andrea. Virtual Globes in the classroom http://www.csiss.org/SPACE/resources/virtual-globes.php#GISdata First published 3/2006
Last updated, UCSB Center for Spatial Studies, 12/2009
General information—What are Virtual Globes?
Virtual Globes, also referred to as Geobrowsers or Earthbrowsers- are Internet-based 3D software engines that display geographic data models on a spherical representation of the Earth (or other planets). A geographic data model is a partial or complete digital representation of a planet that is based on a set of geometric parameters specific to this planet. Terrain data such as elevation is then added to this representation as a base layer, and satellite imagery and aerial photographs are stitched together and draped over the model to give the user the impression of a 3D virtual globe on a 2D screen.
Common functions of Virtual Globes include zoom, tilt, rotate, moving to, querying, adding notations, and overlays. Depending on the software, some Virtual Globes also provide interfaces through which a user can design new tools and functionalities by modifying menu-driven or open-source applications.
Currently, many Virtual Globes have limited capabilities to directly process spatial data and are primarily used for geographic visualization and annotation. However, there is a trend, especially for proprietary Virtual Globe applications, to combine the display features of Virtual Globes with powerful GIS functionalities.
General information—How do Virtual Globes work?
A Virtual Globe is a computer application that is installed on the user’s computer, and enables the user to view remarkable 3D digital representations of the Earth or other planets.
As locally installed programs, Virtual Globes serve as software clients and request imagery from a remote server. Different Virtual Globe clients employ different server technologies, and the look and quality of imagery requested depends on this technology and the images that make up the data model used. Data models, which are stored on a remote server, are comprised of terrain data, aerial photographs, and different satellite images varying in color and resolution.
When a Virtual Globe client requests data from an image server, images are streamed over the Internet from the server to the client. However, downloading high-resolution imagery of the entire earth surface over the Internet would take years, even with a fast Internet connection. To overcome this problem, image tiling, also called pyramid layering, is used to allow users of Virtual Globes to almost seamlessly zoom in from outer space to a 1-foot resolution image.
The concept behind this technology is that the user is first presented with larger, low-resolution images that download faster. As one zooms in or “flies closer”, the low-resolution images are resampled and replaced with smaller, high-resolution images. Blurry images that progressively get sharper are evidence of this process.
To further minimize file size and download time, Virtual Globes also cache files that have previously been downloaded on the local hard drive. If those files are requested again, they are readily available.
The downloaded 3D imagery displayed in a Virtual Globe then serves as background scenery and is augmented with overlays such as those showing administrative boundaries, built features, or annotations.
Each Virtual Globe offers different interfaces to create new and modify existing overlays. For example, Google Earth uses XML-based Keyhole Markup Language (KML) to allow sharing and overlay of geographic data. Some overlays can be created using menu driven interfaces; other, more sophisticated modules need to be developed via scripting. World Wind is fully open-source, making it incredibly flexible; however, its customization flexibility is primarily reserved for programmers rather than the average user.
General information—How do Virtual Globes differ?
Virtual Globes differ widely in regards to their philosophy, intended purpose, functionality, spatial coverage, data quality, and target audience. Since these fundamental differences make a true comparison between browsers impossible, one should focus on strengths and weaknesses as well as appropriateness for a particular use when evaluating them.
Characteristics that should be considered are:
• navigation controls (e.g., zooming, tilting, and rotating)
• information design and display within browser (e.g., authoring tools, overlays)
• information search (e.g., queries)
• creation and adaptability of applications (e.g., scripts, menus, open-source)
• GIS data layers provided (e.g., road network, demographics)
• data exchange (e.g., importing and exporting files)
• data analysis (e.g., terrain analysis), and
• the earth/data model used as backdrop (e.g., type of imagery, datum, and projection).
The Virtual Globes primarily mentioned in this review are the following:
Is part of NASA’s Learning Technologies and has been developed specifically as an educational tool to explore Earth and Moon.
Is published by GeoFusion, a company that offers The GeoMatrix Software Development Kit (SDK) that enables software developers to build interactive digital Earth and planetary-based applications.
Published by Lunar Software, is an easy to navigate earth simulation program.
This is by no means a comprehensive list of all Virtual Globes. Many new globes have been created and achieved widespread use since this report was originally written in 2006. Most notably, Microsoft and ESRI both have introduced sophisticated virtual globes. Microsoft’s Bing Maps service includes an integrated 3D virtual globe within the Internet browser. Upon starting for the first time, a browser plug-in is generally downloaded to facilitate the graphics requirements of the 3D virtual globe. ESRI’s ArcGIS Explorer virtual globe requires a standalone software download to operate, and heavily emphasizes user-selected data and overlay.
An overall trend in virtual globes since the first edition of this white paper in 2006 has been the integration of virtual globes into Internet browsers. Google Earth, NASA World Wind, Microsoft Bing, and others now allow navigation of the virtual globe within the browser. To date, these technologies rely on browser graphics plug-ins such as Adobe Flash, Microsoft Silverlight, or Java. Future virtual globe implementations are likely to incorporate HTML5 graphics objects, and alleviate the need for additional plug-in or software downloading.
General information—Are Virtual Globes free?
Many Virtual Globes can be downloaded from the Internet for free. Some functions of these free versions, however, might be disabled or noticeably limited when compared to professional versions or associated fully-licensed Geographic Information Systems.
• World Wind is free. Complementary data sets can often be downloaded for free or purchased at a minimal fee.
• EarthBrowser has a proprietary, but free viewer as well as a registered version.
• ESRI ArcGIS Explorer is a proprietary product with a free viewer. Advanced services can be created and served using ESRI’s other commercial server products.
• TerraExplorer Viewer is proprietary, but free. TerraExplorer Pro, the software one needs to create files, costs is a commercial, proprietary product.
• Google Earth’s basic viewer is proprietary and free. Google also has commercial, enterprise products. Data can be created and shared using the open KML format. Services can be created using an API. • GeoFusion has a proprietary, free demo viewer.
• Microsoft Bing includes a proprietary, free browser. Services and overlays can be created using their API.
What do I have to consider if I want to use Virtual Globes in the classroom?
Virtual Globes have opened up a tremendous opportunity for teaching about space and spatial concepts. They offer a radically new way of looking at the world (and other planets) and encourage spatial thinking that is reinforced by captivating visual displays. Students usually embrace the new technology, and educators should take this as an opportunity to increase curiosity and enhance learning and teaching about space and science.
For many educators, however, the seemingly endless possibilities for using Virtual Globes in the classroom can be overwhelming, time consuming, and even distracting. New hardware and/or software may need to be installed, new labs written, and a significant amount of time needs to be invested to design new lectures. This particularly becomes a problem for educators who are not as technology savvy and for those who teach in departments with limited resources and IT support.
With the increasing use of Virtual Globes in the workplace, educators in higher education might also feel additional pressure: Whereas in K12 education, the educational potential alone might determine which Virtual Globe is used, in higher education, career preparation and job placement need also be increasingly considered.
To help with the design and dissemination of instructional and informative material, we hope that this page encourages teachers to share their experiences either through this site, user forums related to specific Virtual Globes, or repositories for instructional modules such as Merlot. <br/ When considering a Virtual Globe application for in-classroom use, the following questions should be addressed:
• What is the educational goal?
• How can a Virtual Globe be used to reach that goal?
• What is the technical expertise of the person teaching with and about Virtual Globes?
• Is the available IT infrastructure sufficient?
• What are the hardware requirements for a particular application?
• What is the cost involved if new hardware needs to be installed?
• Does the Virtual Globe developer support education?
• Is technical help and support from a user community available?
• How does the Virtual Globe interface with other applications such as GIS and drawing programs that are already used?
• Can a free viewer be extended to accommodate more sophisticated analysis?
• Which Virtual Globe will students most likely encounter in the workforce?
In general, Virtual Globes should be considered as teaching tools in three capacities:
• complement existing teaching tools (e.g., display data analyzed in a GIS)
• replace existing teaching tools (e.g., globes and maps when teaching coordinate systems) , or
• help define new goals that are impossible to teach with existing tools (e.g., sharing information globally).
Within these capacities, we think that Virtual Globes have a great potential for
• raising geographic awareness
• improving visualization of spatial information
• enhancing spatial data analysis and decision making
• creating flexible learning environments
• fostering national and international collaboration, and
• promoting critical thinking about accuracy, precision, and credibility of spatial data.
Much of the in-classroom use of a Virtual Globe will depend on the teacher’s ability to match an educational goal with a particular browser application. When one judges according to various news groups and forum entries, it appears that so far Virtual Globes have been most readily incorporated in K12 education. The ease with which Virtual Globes can visualize basic geographic concepts supports that notion. But as Virtual Globes will integrate more analytical tools, or as they merge with GIS applications, they will be used more frequently in the undergraduate classroom.
Teaching—Do Virtual Globe developers support education?
Most Virtual Globe developers support education, albeit the motives behind the support are different. NASA World Wind, a federal program, has been developed exclusively as an educational tool. On the other hand, Google, ESRI, and Microsoft are commercial enterprises that introduce their products to students at least partly to establish product familiarity and customer relationships as a means of marketing.
In general, one can evaluate support for education in two areas: “classroom friendliness” of the software itself and administrative support from the developer. The following initiatives and measures are examples of both.
World Wind is part of NASA’s Learning Technology Project (LTP) and it incorporates NASA content with new technology to enhance education in the areas of math and science. World Wind is entirely free, and its extensive imagery provides unique opportunities for science education.
TerraExplorer Skyline’s main applications revolve around the defense and military sector, civil planning, and telecommunication. Although the company does not explicitly promote education on its website, it does offer educational discounts and is, when contacted directly, amenable to negotiations.
For the classroom, TerraExplorer offers a collaboration tool that “allows users to chat, annotate the terrain with text labels and free hand drawing, point using a virtual cursor, and synchronize their flight." Teachers can become the manager of a session and control students’ computer screens.
Google Earth has developed a strong user community that includes an “Education” discussion section and encourages students and educators to share ideas and resources. Whereas students most often exchange placemarks, educators discuss problems encountered while trying to implement Google Earth in the classroom.
GeoFusion’s free viewer might be limited for classroom use, but the full toolkit is extremely customizable and offers almost endless possibilities for education. Developers can create large visualization projects such as the OptIPuter. The technology has also been integrated into ESRI’s ArcGlobe 3D Analyst.
Teaching—What resources are available for teaching?
The resources compiled here are organized by browser. Not all links are directly related to teaching, but the information, contacts, and ideas they provide might be useful in the classroom. At the end of this section, a category has been added that lists general resources (see above) on 3-D visualization, internet mapping, and course development.
• Wikipida entry
• Keyhole Markup Language (KML) tutorial—KLM is Google Earth’s scripting language
• Juicy Geography—Noel Jenkins shares Google Earth related resources that he uses as a Geography⁄ICT Advanced Skills Teacher in Somerset, UK. His special Google Earth page offers a wealth of ideas and is probably one of the best resources for using Google Earth in the classroom. His projects include an imagined urban landscape exercise, and a “really simple” decision-making exercise using Google Earth. Some resources found on this page overlap with sources found on Digital Geography Archive for the “Teaching resources” category.
• Mapping Disaster Zones by I. Nourbakhsh, Nature 439, 787–788 (16 February 2006)
• EarthContest—a travel game using Google Earth
NASA World Wind
• Wikipedia entry
• Walkthrough of World Wind
• NASA World Wind helps solve 3,000 year old mystery of ancient Ithaca
3D visualization teaching resources
• The Terraspark Geosciences is devoted to the research and development of advanced visualization technology across a wide range of disciplines.
• Think Global Nature 439, 763 (16 February 2006) “Virtual globe” software is transforming our ability to visualize and hypothesize in three dimensions. Educators take note. Editorial
• Virtual globes: The web-wide world by Declan Butler, Nature 439, 776–778 (16 February 2006)
• Kastens, Kim A. and Holzman, Neil (2006) The Digital Library for Earth System Education Provides Individualized Reports for Teachers on the Effectiveness of Educational Resources in Their Own Classrooms. D-Lib Magazine, 12(1) January 2006.
• Digital Earth: Building the New World by Y. G. Leclerc 1999
• Geography: Information Visualization in the Social Sciences (may not be available) by S. Orford et.al
Social Science Computer Review, Vol. 17 No. 3, Fall 1999, 289*ndash;304
• Virtual Geography by T. A. Mikropoulos 1996
Can I use Virtual Globes on any computer?
A computer’s hardware and software configurations can drastically influence display quality. Most Virtual Globes have hardware and software requirements listed on their sites. Before downloading an application, check these requirements. Especially the 3D capability of your graphics card, network speed, processor speed, RAM, screen resolution, color depth, and operating system might be important. Most virtual globes tend to be developed for the Windows operating system, though Mac and Linux implementations are also widespread. Browser-based virtual globes continue to reduce operating system dependencies.
What image coverage can I expect?
Image coverage is an important feature of a Virtual Globe since the images provided serve as backdrop for visualization and analysis. Image resolution usually varies from about 1 foot to 1 km per pixel, and the spatial extent includes global and local data sets. Image age can vary from months to years old. As of November 2009, no virtual globe provides widespread real-time imagery.
What data layers are provided?
As mentioned under How do Virtual Globes work? data layers (also referred to as overlays) augment the underlying imagery or orthophotography with thematic features that are of special interest. Data layers can show symbols (i.e., points and lines) that describe features such as buildings or roads, or they can show images overlaid on top of the base images. In addition to static overlays, overlays can be animated and can contain video, audio, and network links.
Besides those overlays that are part of the original installation, many Virtual Globes provide tools and interfaces to create overlays. Sophistication and accessibility of these tools and interfaces varies greatly among Virtual Globes, and their potential use also depends on the user’s skill level: menu-driven interfaces are user-friendly but might be less flexible or might require a licensed version of the software; script or open-source Application Program Interfaces (API) are extremely flexible and often free, but they are meant for skillful users.
Can I import GIS data into Virtual Globes?
Open data formats and specifications such as KML, GeoRSS, and shapefiles have increased the ability to import data into virtual globes. KML has become the de facto data type for virtual globes and geospatial data on the Internet. Most major proprietary GIS packages and open source toolkits support can translate the most popular data formats into KML.