everywhere
Hello,There are many many choices for what you are looking for.I have a Lowrance unit, the LMS337 CDF. It is a GPS chartplotterwith a high resolution 5" color display, 50 and 200 hz sonar unit,and it comes with a speed paddlewheel unit for measuring speedthrough water. My unit is not longer made, the 527 is the newmodel. You can even connect a Lowrance radar to it.Humminbird, Raymarine, Garmin, Standard Horizon, etc. allmake comparable units. I can tell you that Lowrance will probably by the cheapest,and by a lot! I paid $499 for mine at a closeout. The newermodel is about $600 - 700.You can buy them almost everywhere, Westmarine, Defender, BoatersWorld, etc.Good luck,Barry