Reprojection onto ISIN grid

Please enter here to ask a question about any NASA Science related topics!
Post Reply
Posts: 9
Joined: Fri Feb 15, 2008 7:07 pm America/New_York

Reprojection onto ISIN grid

by erehm » Tue Aug 08, 2017 5:16 pm America/New_York

For various reasons, I would like to spatially bin products using the SeaDAS (equivalently GPT) Level-3 Binning, and then reproject onto an ISIN grid.  For example, I would like to spatially bin (AVERAGE pixels) from 4.6 km to 9.3 km resolution, then rewrite as a normal 9.3 km ISIN (e.g., SeaWiFS) grid so that I can use with my own toolset that is built around L3bin products with the ISIN grid.  I can't really figure out how to configure the SeaDAS/Beam Reproject tool to do this.  Is this possible?  If so, can some post the Reproject CRS Sinusoidal Projection Parameters and Output Parameters that achieve this?  

Another thing I would like to do is Reproject a file spatially averaged to 37 km (roughly 8x8 averaging) back to the ISIN 4.6km resolution, again so I can use my existing ISIN-based  tools.   (I can up-sample from 37 km 40 4.6 km using Step, but again, the reprojection step onto an ISIN grid is elusive to me.)

Aside:  This exercise made me realize I don't really understand what happens when a SeaWiFS / MODIS / MERIS / GlobColour L3bin file with ISIN grid is read into SeaDAS/Beam/Step.  I understand it is converted to BEAM-DIMAP format -- does this involve a reprojection in and of itself?  When I navigate the raster of such a file in SeaDAS/BEAM, it is rectangular with the rows (latitudes) of the original ISIN latitudes, but what has happened to the original horizontal ISIN coordinates (longitudes)?  It appears that pixels have been replicated or otherwise interpolated so that the internal raster is rectangular.  Can someone explain this to me?

Thanks in advance,



OB SeaDAS - knowles
Subject Matter Expert
Subject Matter Expert
Posts: 227
Joined: Mon Apr 07, 2008 4:40 pm America/New_York

Reprojection onto ISIN grid

by OB SeaDAS - knowles » Wed Aug 09, 2017 10:01 am America/New_York

What files are you using?  Where do you get the files?  Are they files which are supported by the OCSSW processing code?  Can you use the OCSSW processors: l2bin, etc.?

Although the Level-3 Binning Tool does use an ISIN binning algorithm, it ultimately produces a SMI geographic lat/lon projected file.

If you have a precise mapping you are looking for and you have a file which contains this mapping you can try using the Reproject Tool and selecting your ISIN mapped file in the parameter "use CRS of file". 

Regarding your "Aside" note: Our level-3 bin files cannot currently be loaded into SeaDAS, so again you will need to clarify the source of your files on this. 


Post Reply