Basically anything that tells you what club to use or gives you distance based upon elevation would not be allowed.
Simple things like standard GPS such as hole19 are fine
Common examples of uses of equipment that are allowed and not allowed during a player’s round under this Rule are:
(1) Distance and Directional Information.
• Allowed. Getting information on distance or direction (such as from a distance-measuring device or compass).
• Not Allowed.  Measuring elevation changes, or Interpreting distance or directional information (such as using a device to get a recommended line of play or club selection based on the location of the player’s ball).
• Not Allowed.
 Processing or interpreting playing information from the round (such as club recommendations based on current round distances), or Using any physiological information recorded during the round.
