i dont know if something like this exist but what about this http://forums.civfanatics.com/showthread.php?t=476383
"This module tries to delay the revealing of the full map.
Firstly, without Cartography, civilizations have no means of recording information about the land they have discovered. Any revealed terrain, which is no longer visible to a civilization is concealed once more until they have Cartography.
Secondly, without mastering longitude, a civilization can not accurately map the oceans nor determine the distance to far off continents. Learning Engineering, Divination or Necromancy technologies provide means to master longitude. Until a civilization can determine longitude then areas (oceans/continents) in which they do not have a city, which have been revealed but are no longer visible, will be concealed once more."
"This module tries to delay the revealing of the full map.
Firstly, without Cartography, civilizations have no means of recording information about the land they have discovered. Any revealed terrain, which is no longer visible to a civilization is concealed once more until they have Cartography.
Secondly, without mastering longitude, a civilization can not accurately map the oceans nor determine the distance to far off continents. Learning Engineering, Divination or Necromancy technologies provide means to master longitude. Until a civilization can determine longitude then areas (oceans/continents) in which they do not have a city, which have been revealed but are no longer visible, will be concealed once more."