LAC (Local Area Coverage):Contains full-resolution (1.1 kilometer) data.
GAC (Global Area Coverage): GAC is coarse resolution data obtained by subsampling the LAC data every fourth scan line and every fourth picture element (pixel),which gives a resolution of 4.5 km. SeaWiFS acquires 15 GAC swaths a day, each swath 1500 km wide starting from the Arctic Ocean and following the orbital ground track to Antarctica. A granule is a single swath of consecutive scans obtained as the satellite orbit moves from the north polar region to the south polar region. A single swath therefore contains approximately 40 minutes of data.
Level 2 browse product: Consists of the Chlorophyll a concentration values along with appropriate masks, and is 9 km resolution. It is generated from the corresponding Level 2 product.
HRPT: On the ground High Resolution Picture Transmission (HRPT) stations obtain raw radiance data which are processed to Level 1A by the receiving station, then sent to the SeaWiFS Project and subsequently to the DAAC. For HRPT data, each scene is comprised of one satellite pass.
MLAC (Merged Local Area Coverage): Consolidates all available full-resolution (LAC and HRPT) from a single orbit. In geographic regions with multiple HRPT stations, overlapping scenes are evaluated to select a single best quality scan in order to eliminate duplicate scans. It reduces geographic overlap from multiple receiving stations and maximizes data quality.
