By the way, having vertical information on landforms is helpful while entering harbors, getting a feel for the features (w/ satellite photo overlays) etc.

I've not found the graphics for the underwater features too helpful -- but then I'm not fishing.

Whether all the information is processed, but only some items are "plotted" on the screen is an interesting question. I think that some of the software packages handle it differently.

If you turn-on "tides and currents" in MaxSea on the Furuno or PC, I believe it computes the currents and tides WORLDWIDE. You might be displaying only a 2 mile by 3 mile area on the screen, but the processor is busy trying to figure-out all the World's data as you flip through the time sequences.

The systems' architecture of how the data is crunched makes a big difference on the chart plotters -- more so that the usually more robust PC's or mobile units that have lots of RAM, a decent video chip or card, and very fast processors.