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HOME > Monitoring_and_Data > Oceanic and Atmospheric Data > Reanalysis: Atmospheric Data > wgrib2 questions
 

wgrib2: limitations
    Limitations on 32-bit computer
  1. The maximum grib file is limited to 2GB unless the file is read sequentially.
    i.e., cat grib_file | wgrib2 - (rest of options)
  2. large grib messages and grids will use buffer space and exhaust physical memory.
  3. grib message is limited to 2GB (fixed v2.0.4)
  4. Any buffer greater than 4GB is a problem.
  5. The maximum grib message is limited to 2GB to 4GB (depending on routine)
  6. The maximum number of grid points varies by routine from to 2G to 4G (grib2 standard=4G).
    The amount of addressable memory will be a limitation.
  7. The maximum bit precision of a complex-packed file is 25.
    Limitations on 64-bit computer
  1. The maximum number of grid points varies by routine from to 2G to 4G (grib2 standard=4G).
    Low priority to get the routines to 4G.
  2. -new_grid is limited to 2G grid points by the fortran library.
  3. grib message is limited to 2GB (fixed v2.0.4)
  4. The maximum bit precision of a complex-packed file is 25.
    Limitations on computer with 64-bit pointers and 32-bit long integers
  1. Similar to 32-bit limitations.
    Supported Unpacking Schemes
  1. simple
  2. simple with log preprocessing
  3. complex with bitmaps or special values
  4. jpeg2000
  5. png
  6. ieee
  7. RLE
  8. CCSDS/AEC
    Supported Packing Schemes
  1. simple
  2. complex with bitmaps or special values
  3. jpeg2000
  4. ieee
  5. CCSDS/AEC
    Grid Support Levels: geolocation
  1. nothing
  2. diagnostic inforamtion
  3. latitude/longitude of the grid points are calculated (spherical earth)
  4. latitude/longitude of the grid points are calculated (aspherical earth)
    Grid Support Levels: ipolates (-new_grid)
  1. nothing
  2. can be an input grid for -new_grid
  3. can be an input or output grid for -new_grid
    Grid Support Levels: -small_grib
  1. nothing
  2. can be an input grid for -small_grib
    Grid support:
  • lat-lon: full support
  • Lambert conformal: full support
  • Polar stereographic: full support
  • Mercator: full support
  • Gaussian: all but -small_grib
  • thinned lat-lon grids: only geolocation
  • rotated lat-lon grids: only geolocation
  • space view perspective: only geolocation
  • Albers equal area: only geolocation
  • Lambert Azimuthal equal area: only geolocation
  • staggering all above except for Gaussian: only geolocation
  • irregular grid: only geolocation
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