Determining a boundary enclosing a region of interest for a body of water

A marine device located within a marine vessel, the marine device comprising:

• a display;
• a memory unit configured to store an offset direction and an offset distance associated with a boundary defining mode;
• a location determining component configured to generate geographic location data indicative of a geographic location of the marine device while the marine vessel navigates a body of water having a natural shoreline along a perimeter of the body of water;
• a user interface configured to receive the offset direction and the offset distance from the traveled path to the natural shoreline;
• and
• a processing unit coupled with the display, the location determining component, the user interface, and the memory unit, the processing unit configured to:
• determine a path traveled by the marine vessel based on the geographic location data,
• determine an offset based on the offset direction and the offset distance,
• determine a boundary formed by applying the determined offset to the traveled path, the determined boundary at least partially enclosing a region of interest and corresponding to the natural shoreline,
• associate a water depth of zero with the determined boundary, and
• control the display to present a map including the region of interest;
• wherein the offset direction is a side of the marine vessel for which the offset distance is to be applied.