revealed

Does anyone have an algo suitable for a tuner panel that determines if a resource (e.g., Iron) should be revealed to a player. That is, has the player researched the required tech (e.g., Bronze Working)? I'm writing a tuner panel to identify the location of resources on the map and would like to...

For some odd reason, whenever I play an Earth map, the Incan or Aztec starting location is shown. This makes the gameplay odd as the scale is very small even in the start of the game.