As the ocean evolves quite slowly and regularly, it is interesting to track ocean structures such as eddies over the latest three or four maps. With experience, you can can use altimetry maps to forecast how these structures are likely to evolve.

CATSAT software lets you overlay altimetry data on ocean color or surface temperature maps.

CATSAT software is not designed specifically for navigation, but it does provide all the basic features of a navigation software. For example, its GPS interface lets you keep track of your vessel's heading, speed and position. It also has a dead-reckoning cursor. Hence you know at one sight how far you are from your favorable fishing ground.