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  • Three reader can read the data. SeaDAS reader is 'intended', MODIS and NetCDF are 'suitable'
  • NetCDF reader provides no geo-location and band names are different to MODIS and SeaDAS and provides only raw count data
  • MODIS reader has good geo-location and provides data as radiance
  • SeaDAS reader has bad geo-location and provides data as reflectance
  • Version of our SeaDAS reader is higher as the one from SeaDAS.

Requirements and Problems

#TitleUser StoryImportanceNotes
1Geo-location of MOD021KM data is inaccurateWhen reading this type of data with the SeaDAS reader the geo-location has a shift of several pixels(star)(star)(star)(star)(star)
  • If the SeaDAS reader is removed it is not deterministic any more which reader is selected. NetCDF and MODIS reader claim to be 'suitable'.
2Provide data as radiance and/or reflectance valuesThe data is given as raw count values and conversion factors to radiance and reflectance values. User shall either be able to chose between radiance and reflectance or both values shall be provided(star)(star)(star)(star)(star)
  • On the branch 'MODIS21KM_patch' in the BEAM repository there has been a system property beam.modis.MOD021KM.readAs introduced in order to allow users to switch between radiances and reflectances
3Geo-location is wrong if scene crosses dateline

If the data is read by the SeaDAS reader the geo-location is wrong if scene crosses dateline. This is caused by not constructing the longitude tie-point-grid with the DISCONT_AT_180 option

(star)(star)(star)(star)(star)
  • This is already fixed for BEAM (BEAM-1740) it needs to be ported to SNAP.
  • Actually the SeaDAS guys need to be informed so they can fix it in their implementation.
4Version of our SeaDAS reader is higher as the one from SeaDAS. Use SeaDAS reader directlyCurrently we use our own copy of the SeaDAS reader. This gives us the freedom to change code but is not code practice.(star)(star)(star)(star)
  • In SeaDAS reader the problems we identify shall be fixed.
  • SeaDAS shall make a big version increment in order to overtake us.Before they

 

Questions

Below is a list of questions to be addressed as a result of this requirements document:

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