<html><head></head><body><div class="yahoo-style-wrap" style="font-family:times new roman, new york, times, serif;font-size:16px;"><div dir="ltr" data-setdir="false">Cliff, what manufacturer/model sounder are you using for altitude? Do you have it interfaced with your computer or is it a separate unit? I'm looking at NMEA sounders which are relatively easy to interface with microprocessors but are expensive. Analog depth sounding transducers are much cheaper but I don't know how they present their information.</div><div dir="ltr" data-setdir="false"><br></div><div dir="ltr" data-setdir="false">Jon</div></div></body></html>