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Topic Products and Algorithms / Satellite Data Products & Algorithms / Level-3 image resolution (locked)
By Claire
Date 2004-07-02 15:00
Hi,
With Level-3 composite images there are no options available when downloading the images and there is no option to extract a composite image of an area of interest for downloading. The only information offered on these files are that they are of 9km resolution. When viewing these files in SeaDAS they are of little or no use when looking at local areas of interest eg the Irish Sea, as the pixel size is very large.
Has SeaDAs a function that will merge the level 2 files to create a composite image for a specific area of interest and thus remove the negitive effects of cloud cover and create monthly/weekly averaged images?
Or is it possible to get composite images of a more suitable resolution for use in local area studies?
Thanks :?
With Level-3 composite images there are no options available when downloading the images and there is no option to extract a composite image of an area of interest for downloading. The only information offered on these files are that they are of 9km resolution. When viewing these files in SeaDAS they are of little or no use when looking at local areas of interest eg the Irish Sea, as the pixel size is very large.
Has SeaDAs a function that will merge the level 2 files to create a composite image for a specific area of interest and thus remove the negitive effects of cloud cover and create monthly/weekly averaged images?
Or is it possible to get composite images of a more suitable resolution for use in local area studies?
Thanks :?
claire,
for seawifs data, the level-3 standard products are only available in 9 kilometer resolution with the two exceptions being land surfance reflectance and ndvi which are also available in k 4 kilometer. the individual files either in image or hdf format are available for download at all temporal periods either on the web at:
http://oceancolor.gsfc.nasa.gov/cgi/level3.pl
or via ftp at:
ftp://samoa.gsfc.nasa.gov/pub/sdps/V4/L3SMI/
for modis/aqua, both 4 and 9 kilometer data are available for all products on the web at:
http://oceancolor.gsfc.nasa.gov/cgi/level3.pl
and via ftp at:
ftp://oceans.gsfc.nasa.gov/Aqua_SMI/
since all the level-3 products are in the same projection, it is a very simple process to extract the same geographic region from all the level-3 standard mapped (smi) files and should be easily done within seadas.
most people that work at the local scale using the 1 kilometer data which is not available globally for seawifs but is available for modis/aqua, either process the data to level-2 themselves or use the level-2 data that we make available and then map the products to whatever region of interest they want to study and i believe there is the abilitity to average a number of scenes together once they are all mapped to the same projection to create a time average product that removes the clouds and fills in the data gaps.
hope this helps,
gene
for seawifs data, the level-3 standard products are only available in 9 kilometer resolution with the two exceptions being land surfance reflectance and ndvi which are also available in k 4 kilometer. the individual files either in image or hdf format are available for download at all temporal periods either on the web at:
http://oceancolor.gsfc.nasa.gov/cgi/level3.pl
or via ftp at:
ftp://samoa.gsfc.nasa.gov/pub/sdps/V4/L3SMI/
for modis/aqua, both 4 and 9 kilometer data are available for all products on the web at:
http://oceancolor.gsfc.nasa.gov/cgi/level3.pl
and via ftp at:
ftp://oceans.gsfc.nasa.gov/Aqua_SMI/
since all the level-3 products are in the same projection, it is a very simple process to extract the same geographic region from all the level-3 standard mapped (smi) files and should be easily done within seadas.
most people that work at the local scale using the 1 kilometer data which is not available globally for seawifs but is available for modis/aqua, either process the data to level-2 themselves or use the level-2 data that we make available and then map the products to whatever region of interest they want to study and i believe there is the abilitity to average a number of scenes together once they are all mapped to the same projection to create a time average product that removes the clouds and fills in the data gaps.
hope this helps,
gene
Topic Products and Algorithms / Satellite Data Products & Algorithms / Level-3 image resolution (locked)