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Starting Point-Teaching Entry Level Geoscience > Teaching with Google Earth > What is Google Earth?
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What is Google Earth?



Google Earth with Plate Boundaries, Volcanoes, Faults
Google Earth with the Volcanoes layer visible, and tectonic plate boundary data from USGS displayed
Google Earth is a geobrowser that accesses satellite and aerial imagery, ocean bathymetry, and other geographic data over the internet to represent the Earth as a three-dimensional globe. Geobrowsers are alternatively known as virtual globes or Earth browsers. Google also refers to Google Earth as a "geographic browser." Other examples of geobrowsers are NASA's World Wind, ESRI's ArcGIS Explorer, GeoFusions's GeoPlayer, and EarthBrowser by Lunar Software. Google Earth is available on the web for free as well for purchase in more advanced versions. While the free version offers numerous features that are useful in educational settings, the Pro version offers additional capabilities such as higher resolution printing and saving of images and the ability to open ESRI shapefiles. The free version of Google Earth as well as Pro are available through Google's Explore, Search, and Discover page.

The Three Versions of Google Earth
Each of these versions of Google Earth can be used to read and create data in KML (Keyhole Markup Language) format, which enables educators, students, and other users to share data. For a comparison of these products, see Which version of Google Earth is right for you?. However, the chart is a bit out of date as it does not mention that the free version can also open GPS files, which is a very useful feature for education.

Google Earth provides search capabilities and the ability to pan, zoom, rotate, and tilt the view of the Earth. It also offers tools for creating new data and a growing set of layers of data, such as volcanoes and terrain, that reside on Google's servers, and can be displayed in the view.

It also uses elevation data primarily from NASA's Shuttle Radar Topography Mission (SRTM) to offer a terrain layer, which can visualize the landscape in 3D. For some locations, such as most of the western portion of the United States, the terrain data is provided at significantly higher resolutions.

Google Earth is not a Geographic Information System (GIS) with the extensive analytical capabilities of ArcGIS or MapInfo, but is much easier to use than these software packages.

It is available for several operating systems, namely:

Google Maps and the Google Earth API are products that include some of the features of Google Earth, and can used to embed interactive maps into web pages. The Google Maps site was originally created as a service for providing driving directions. But curious enthusiasts examined the JavaScript code that supports the service, and quickly learned to create their own customized Google Maps. Subsequently, Google made the details of the Google Maps API public for all to use for creating customized user interfaces. In contrast, the Google Earth API was expressly created to enable the public to create customized three-dimensional map interfaces in web pages that have the look and feel of Google Earth. Both Google Maps and the Google Earth API offer the same imagery that is available through Google Earth, along with the capability of adding features, such as customized buttons, forms, and panels that can work with and display data. To create these specialized applications, developers use AJAX, which combines writing code in JavaScript with accessing data that is stored in XML format. In fact, KML is actually a form of XML. Google Maps can be used in all major web browsers and platforms, however, the Google Earth API is currently available for Windows and the Macintosh, but not Linux. It is restricted to a subset of browsers, and requires the user to download a plugin. Another mapping technology available through Google is the Google Mapplets API. Mapplets are small applications that run within Google Maps rather than being hosted on a third-party web site.

Coding in JavaScript is not needed in order to create simple Google Maps. Setting up simple customized Google Maps and posting them on the web requires logging into a free Google account and activating the My Maps tab. A set of tools enables the creation of points, lines and polygons on the map. The map is assigned a url that can be used to share it students or others. HTML code is also displayed that can be used to embed the map into a web page. A web browser is sufficient for viewing maps created in this manner. A KML file that has been stored on a web server can be opened in Google Maps by entering its url in the Google Maps search box. While easy to create and share, these simple Google Maps are not as feature-rich as Google Earth.

There is even a version of Google Earth for the iPhone. This product can display the same imagery that is available on the desktop versions, perform searches, and link to Wikipedia articles about places of interest, but it does not have all the features of the desktop versions of Google Earth.




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