is it possible to have the gps location while offline with the nexus 7?
I had this issue - it isn't that a fix doesn't come, it is just that it is taking a very long time to get a fix.

This is due to the lack of the downloaded aGPS data - it can't download the data, and so has to rely on solely GPS satellited, which takes ages.

If you have been disconnected from the internet for a while, then you will suffer from these effects. aGPS data is cached for a few days, or when you change location, so if you just disconnected, GPS should work for a while afterwards. 

(You should also check to make sure that the Google System is enabled for location use)