Investigate Portal (3.5e Spell)

You learn information about the destinations of the target portal. On the first round, this spell behaves as Discern Portal Destination. Each subsequent round, you may take one of the following actions:
 * Find a new destination: You learn of a randomly-selected destination that the portal has that you didn't already learn about this investigation, and begin to focus on it. If you already know of all of them, you instead learn that.
 * Focus on a known destination: You begin to focus on a destination you already know about.
 * Determine a piece of the key: You learn one piece of the key to the destination you are focusing on. You also learn if you have uncovered enough parts of the key to have a complete key.  If you have uncovered all of the parts to the key, you learn that when you try to find a new one.
 * Determine a complete key: The DM secretly picks a random key to the destination you are focusing on. You learn which parts you already know about go to that key, and whether or not that is a complete key.
 * Project a sense through: You may project any one sense you have (hearing, smell, sight, or an exotic sense like tremorsense or blindsense) through to the destination you are focusing on. If you do this on two consecutive rounds, you get two senses on the second round.  If your blindsense or blindsight or whatever is based on another sense (such as hearing), you must project the basic sense through first (it comes through deadened enough to deny you your better sense).  Until you have spent three rounds probing with your senses, all creatures and objects on the other side have total concealment regardless of what senses you use, even sight or blindsight.