After experiencing a CTD while trying to save the game I re-entered the game reloaded the autosave file.  (Saved immediately first link below.)  On reload all previously explored resources, forests and rivers outside of sight of units/city are now invisible.  I went back to an earlier save (second link) and the problem is also present in this.  Notably though if you move the units NE (onto the life shard adjacent to the city) a number of resources, far exceeding line of sight become visible on the map again.  I was unable to get a similar result with the later save.

http://dl.dropbox.com/u/14105530/Solo5.rar

http://dl.dropbox.com/u/14105530/Solo3.rar