I am a graduate student in Bowling Green State University, intend to use SeaWiFS data dated July 01, 2000 and September 27, 2000 over Lake Erie for research purpose. I would like to point out one thing that, the data I have downloaded seems to be distorted, thus deviates from the original geographical extents. The L1A_MLAC image is the best among all of these images but it is distorted and not atmospherically corrected. The L1A_GAC image looks oblique and it seems no information can be retrieved from that image. The L2_GAC image is a rotated image. Lake Erie looks as elongated in NS direction in stead of it's NW-SE trend. Eventually, the L2_MLAC is also rotated to a great extent similarly as L2_GAC. I tried to solve this problem by georeferencing these through ERMAPPER software, but I couldn't bring them back to the original geographical extents they should have. May I know the Datum, Projection, Coordinate type, Cell size, Units and Rotation of each of these data.

Would you advise me to use L1A_MLAC data, but as it is not atmospherically corrected would you please let me know how shall I be able to get L1A_MLAC data atmospherically corrected and how shall I be able to georeference it such that it will match the exact geographic extent.

Thanks

Padmanava Dash
pdash@bgnet.bgsu.edu

dear padmanava,

the product information you need can be found at:

http://oceancolor.gsfc.nasa.gov/ocformats.html

with detailed product specifications available as pdf files under each section.
please read these descriptions as they should answer most, if not all of the
questions that you have.

lthe level 1 and level 2 data are in satellite swath coordinants and can easily be
mapped to whatever grid system you want using the freely available software
called SEADAS that you can download at:

http://seadas.gsfc.nasa.gov

hope this helps.
regards,
gene