question about humminbird basemap upgrade

hey guys,

I plan on fishing some of the pascagoula river using my humminbird 597 hd di. It seems the basemap
does not include any of the pascagoula river north of I-10. What should I do to update the map to show the whole river system and creeks? Thanks in advance.
joey

No upgrade for the built in mapping. you must by a Navionics chip for your region to get better mapping. Go to the Navionics website and view your region chip to see if your river is covered.

Thanks for the info. Do you have to buy a navionics chip or can you download the info onto an sd card?

Joey, You would purchase a Navionics map card.
They do offer updates as a download but you have to have their card.

Deborah @ Humminbird

Thanks again for the assistance!