Google Earth

This is really the coolest device that I have ever seen!!

Google Earth. It lets you view anything on planet earth. I feel like I'm playing Sim City again. But this time for real.

http://earth.google.com/

Google Earth is a free virtual globe developed by Google. It is available for use on personal computers running Microsoft Windows and versions for Linux and Mac OS will be released in fall 2005. Google Earth overlays satellite imagery, aerial photography and GIS information over a 3D model of the Earth.

Overview
Google Earth uses U.S. public domain, chartered flight and Keyhole satellite images to allow customized use of Google Maps with, for example, map images with town and street names overlaying satellite images. For some areas, these overlays are available even though Google Maps by itself does not provide them.

The location of some overlay information--for example, the railways in the Netherlands--is available with little precision, giving odd results when zooming in. These kinds of errors are due to underlying errors in the GIS data describing each point. Such errors are gradually being reduced as the technology progresses to additional decimal places of accuracy, especially as higher-precision and denser benchmark points are established and the target points triangulated and correlated.

The images, which have been photographed almost vertically, can optionally be viewed as if looking at a selectable tilt angle: with "far away" at a smaller scale than "nearby", and with smaller scale in forward/backward direction than in left-right direction. Terrain elevation data are also processed.

It also incorporates Google Local and directions. See also KML (Keyhole Markup Language).


3D Buildings
A feature implemented by Google after its acquisition of Keyhole is a 3D Skyline for (as of July 2005) 35 Cities. This data is provided by ITSpatial as part of Google's license of Sanborn's Citysets data suite. This feature is limited to displaying grey overlaying "blocky" buildings, while the full-version of Citysets renders buildings with significantly more detail.


Specifications

Google Earth comes with atmosphere effects, seabed and a simplified planetariumBaseline resolutions
U.S.: 15 m
Global: Generally 15 m (some areas such as certain oceanic islands are in extremely low The Blue Marble resolution, e.g. [1])
Typical high resolutions
U.S.: 1 m, 0.6 m, 0.3 m, 0.15 m (extremely rare; e.g. Cambridge, Ma.)
Global:
Altitude resolution:
Surface:
Seabed: Not applicable (the seabed is "printed" on the spherical surface).
Age: Usually less than 3 years old.
Google Earth is unlikely to operate on older hardware configurations. The most recent downloads available document these minimum configurations:

Windows 2000, or XP
Pentium 3, 500Mhz
128M RAM
400MB disk space
Network speed: 128Kbits/sec
3D-capable video card with 16Mbytes of VRAM
1024x768, "16-bit High Color" screen
The most likely mode of failure is insufficient video RAM: the software is designed to declare failure if 16 MB of video RAM is not available. The next most likely mode of failure is Internet access speed. Except for the very patient, DSL is required. Again, resolution is not uniform. Compare the resolution of these older B&W data:

http://terraserver-usa.com/image.aspx?T=1&S=10&Z=17&X=3284&Y=20743&W=1
versus what is currently available with Google Earth in color

View with Google Earth
In this case, the TerraServer-USA data can identify individual trees but its data is structured in cumbersome tiles. As with much GIS data, the utility of the data is application-dependent for the purpose of determining if resolution is sufficient. Also note that from a usability point of view, TerraServer loses its center point when one zooms in and out where Google Earth browsing is smooth; a clear benefit, but at the price of the somewhat demanding requirements imposed upon the video card.


Google Earth Plus
Google Earth Plus is an individual-oriented paid upgrade to Google Earth and adds the following features:

GPS integration – read tracks and waypoints from a GPS device.
Higher resolution printing.
Customer support via email.
Annotation – adds draw/sketch tools for richer annotations (can be shared as KML).
Data importer – read address points from CSV files.

Google Earth Pro
Google Earth Pro is a business-oriented paid upgrade to Google Earth that has even more features than the "Plus" version. The Pro version is capable of running additional add-on software[2]..

From Wikpedia
http://en.wikipedia.org/wiki/Google_Earth