wgrib2: -scaling
Introduction
In grib, grid values are usually stored as
grid_value = (ref_value + I*2**bin_scaling)) * 10**decimal_scaling.
I is an positive integer
ref_value = 32-bit IEEE floating point number
binary_scaling = -127..127
decimal_scaling = -127..127
number_of_bits = the smallest N such that I < 2**N
note: WMO does not place a maximum value of the number of bits
however, implementations do have limits. The limits will
vary by software package and procedure.
This is not an absolute as the grid point values can be stored as
a spectral coefficients, IEEE floating point values and other formats.
The -scaling option
prints the binary and scaling factors, the reference value and the number
of bits used for the integer I.
Usage
-scaling
Example
$ wgrib2 gep19.t00z.pgrb2af180 -scaling -for 13:14 -v -packing
13:473374:scaling ref=2.32109e+06 dec_scale=-3 bin_scale=4 nbits=16:packing=grid point data - jpeg2000 compression,j val=(2.32109e+06+i*2^4)*10^-3, i=0..65535 (#bits=16)
14:528630:scaling ref=2215 dec_scale=-1 bin_scale=0 nbits=10:packing=grid point data - jpeg2000 compression,j val=(2215+i*2^0)*10^-1, i=0..1023 (#bits=10)
See also:
-scale
-set_scaling
-grib_max_bits
|
www.nws.noaa.gov 
