There is too much confusion surrounding this term "Nadi Astrology". Different people perceive it differently. Few people associate Nadi Astrology with thumb impression and palm leaves. Some will associate it with Nakshatra based astrology system. Some even associate it with Bhrigu Samhita, Arun Samhita, Lal Kitab et. Due to ignorance and lack of understanding, this rich Indian tradition of Nadi is being spoiled. This video, for the first time on Internet, defines what exactly is Nadi Astrology.
If you prefer reading than watching video, here is the transcript of Nadi Astrology Video.