[ Thanks to LinuxLinks for this link.
]
“In the past there have been attempts to reverse engineer Google
Earth and implement its features in an open and extensible way.
However, these actions have understandably been frowned upon by
Google. Instead we prefer to see the development of open source
virtual globe software which uses freely licensed or public domain
data. Whilst the development of open source virtual globe
applications may not, in itself, encourage Google to release its
application or data under a similar license, it does give users the
option to be able to have the freedom to do what they want. This
route also helps to foster greater user community support to drive
development often in the form of add-ons and plug-ins.“There are a number of applications which are credible open
source alternatives to Google Earth. Whilst none of the software
applications featured in this article have all of the features
offered by Google Earth (although some offer some different
features), and they are not exactly comparable, they are all worthy
of investigating.”