I wish to clarify with users who are using Google Earth portable solution. As per portable solution link http://www.google.com/enterprise/earthmaps/portable.html, we can create part of globe and create offline map to use it.
However FAQ section in : http://www.google.com/enterprise/earthmaps/earth_enterprise_faq.html mentioned as below: Does the Google Earth Portable solution allow you to use Google's imagery? No, the Google Earth Enterprise portable solution is intended to be used in situations where your employees need to access your internal imagery and mapping data. Google does not provide customers with Google licensed data for portable use. Google has many partners that provide custom Google Earth Enterprise portable solutions with high resolution imagery.
Then i am not sure how to use portable solution in offline without Google's imagery data. Any experiences or details on this solution are welcome. Thanks