Electronic tide meter, method for calculating a high/low tide time and computer algorithm for executing the same

An electronic tide meter for calculating when a high tide or a low tide occurs, comprising:

• operating means for determining first tide level data having a first time interval using a tide level estimating equation for calculating a tide level based on a selected calendar date and a selected geographic area, for determining when a sign of a displacement value between successive first tide level data determined using the tide level estimating equation changes, for determining second tide level data having a second time interval shorter in duration than the first time interval from the tide level estimating equation at around a time that the sign of said displacement value changed, and calculating a time of a tide dependent on the second tide level data.

An electronic tide meter for calculating when a high tide or a low tide occurs, comprising:

• operating means for determining first tide level data having a first time interval using a tide level estimating equation for calculating a tide level based on a selected calendar date and a selected geographic area, for determining when a sign of a displacement value between successive first tide level data determined using the tide level estimating equation changes, for determining second tide level data having a second time interval shorter in duration than the first time interval from the tide level estimating equation at around a time that the sign of said displacement value changed;
• and calculating means for calculating an extreme value by interpolating the second tide level and calculating a time of a tide dependent on the second tide level.