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[McIDAS #MUB-377647]: Converting MciDAS to NetCDF navagation issue



Hi David,

First, an overall comment: the question you are asking is not really
McIDAS-related other than one form of the data you requested from CLASS
is McIDAS AREA.

re:
> I am having an issue w/MciDAS areas retrieved from NOAA CLASS site.  I
> extracted the same region/time and requested it in 2 different output
> formats: Area and NetCDF.(both 16Bits/Pixel and highest possible
> spatial resolution(1km).  When plotting the region out using NCL I use:
> 
> AreaToNetCDF.jar areafile netcdf-file.nc -CBRIT
> 
> to convert the area file to a usable format for NCL(ie NetCDF).  I then plot 
> out the
> same file using the NetCDF file gotten directly fron CLASS.
> 
> When comparing the two images it appears that the navigations are slightly 
> different.

This may be due to how the NOAA folks are creating either the McIDAS AREA or
netCDF files.  I can't comment on this in any detail since I don't know what
their procedures are.

re:
> The image using the converted area file is shifted slightly to the N+W of the 
> image
> created from the CLASS NetCDF output file.

The images you attached to your inquiry don't seem to exhibit much, if any, 
shift,
but they do show slightly different features.  This suggests that there was some
sort of interpolation done in the creation of one or both of the images.  This
could be caused by a remapping of the image when creating either the AREA or
netCDF by NOAA.

Question:

- do you know what projections are in the files you got from CLASS?

  I.e., are they in native satellite (i.e., GOES) projection, or have
  they been remapped into rectilinear?

re:
> When doing a ncdump -v lat for each file I can see that this shift is 
> reflected
> in the boundary points of each file, despite both files having the same 
> number of
> lines/elemants.

Question:

- shifted by how many pixels?

re:
> Any insight you can provide would be greatly appreciated...

Can you provide an AREA and netCDF pair of images (meaning the exact
same time) so I could poke around with them?

Cheers,

Tom
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Ticket Details
===================
Ticket ID: MUB-377647
Department: Support McIDAS
Priority: Normal
Status: Closed
===================
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