To answer the original question, yes, you don't have to use a split screen. One of the many views supported is sonar-only. In fact, you can go to town customizing the screens in terms of what information is displayed, the view, the layout, the colors, etc.

I have the Echomap 43cv, which has maps. But even the GPS without maps function is surprisingly useful for navigating to particular location and for finding your way back to honey holes.

D7