I find that all 3 features, 2d, DI, and SI contribute to the perfect crappie combination. The proper settings, and use, of these functions equals more fish on the hook. One caution - - - Humminbird units with both SI and DI have a compromise with the DI clarity; it does not give nearly the resolution of a dedicated DI unit and transducer. (EXAMPLE) - I have a597CI HD DI that I primarily use for DI only. - - My main unit,
899CI HD SI NAV COMBO is for all other functions. The 899 DI stinks compared to the 597 DI.