PC Based Bathymetric maps

[David Hope]

I am looking for a PC based program that will give details on depths, terrain, etc that is more accurate/detailed than standard navigation software. I thought I read about something that was out to the general public that could be tied to GPS and is very accurate showing depths, terrain, etc as you cruise. In fact the article (some sales man) said with this new program/mapping you did not necessarily need a depth finder/sonar in the areas covered by this system. I will always have a depth finder/sonar but I thought this could be a good addition. Wishful thinking or is this real?

 

[DDW]

Navionics and possibly others have much more detailed bathymetric charts than the official national data, in part crowd sourced. I have used the Navionics version extensively. You are warned they are Not For Navigation. Sometimes they are quite accurate, matching well what an expensive side scanning sonar reports. Sometimes they are not very accurate. Occasionally they are a complete fantasy. The sources of information are not reported, so you just don't know until you see it with your own sonar, or feel it with the keel.